Feasibility and safety of early cardiac rehabilitation using remote electrocardiogram monitoring in patients with cardiac surgery 

Feasibility and safety of early cardiac rehabilitation using remote electrocardiogram monitoring in patients with cardiac surgery | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Feasibility and safety of early cardiac rehabilitation using remote electrocardiogram monitoring in patients with cardiac surgery Yeon Mi Kim, Bo Ryun Kim, Sung Bom Pyun, Jae Seung Jung, Hee Jung Kim, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4489270/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: To evaluate the safety and feasibility of a remote electrocardiogram monitoring-based cardiac rehabilitation (CR) program during an early postoperative period in patients with cardiac surgery. Methods: Five days after cardiac surgery, patients were referred to a CR department and participated in a low-intensity inpatient CR program. During 2 weeks of the home-based CR period after discharge, patients participated in aerobic and resistance exercises. electrocardiogram data were transmitted to a cloud where researchers closely monitored them and provided feedback to the patients via telephone calls. Grip strength (GS), 6-min walk distance (6MWD) and self-reported questionnaires were measured at three different time points: 5 days postsurgery (T1), predischarge (T2), and 2 weeks after discharge (T3). Squat endurance tests and CPET were performed only at T2 and T3. Results: Sixteen patients completed the study, seven of whom underwent coronary artery bypass graft surgery (CABG). During the period between T2 and T3, peak VO2 improved from 12.39±0.57 to 17.93±1.25 mL/kg/min (p<0.01). The squat endurance test improved from 16.69±2.31 to 21.81±2.31 (p<0.01). In a comparison of values of time points between T1 and T3, the GS improved from 28.30±1.66 to 30.40±1.70 kg (p=0.02) and 6 MWD increased from 249.33±20.92 to 387.02±22.77 m (p<0.01). The EQ-5D and SF-36 improved from 0.59±0.03 to 0.82±0.03 (p<0.01) and from 83.99±3.40 to 122.82±6.06 (p<0.01), and KASI improved from 5.44±0.58 to 26.11±2.70 (p<0.01). Conclusion: Early remote ECG monitoring-based CR programs are safe for patients who underwent cardiac surgery. Additionally, the program improved aerobic capacity, functional status, and quality of life. Trial registration : This study was registered with the Clinical Research Information Service (CRIS) under the trial registration number KCT0006444 on August 13, 2021. cardiac rehabilitation telerehabilitation cardiac surgery exercise test walk test ambulatory electrocardiography monitoring Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Background In South Korea, a 25% increase in cardiovascular mortality was observed over the past decade, making it the second leading cause of death in 2022 [ 1 ]. Each year, approximately 10,000 patients are admitted to intensive care units following cardiovascular surgery, with a rising trend observed between 2010–2019. Aortic surgery has demonstrated the highest mortality rate, followed by coronary artery bypass grafting (CABG) and valve surgery [ 2 ]. Cardiac rehabilitation (CR) improves exercise capacity, quality of life, hospital admissions, and mortality rates. Clinical guidelines from Europe, America, and Korea strongly recommend the incorporation of CR for patients with congestive heart failure, valve disease, coronary heart disease, and postopen-heart surgery [ 3 – 6 ]. Cardiac rehabilitation comprises three phases. Phase 1 begins with early mobilization from intensive care units, aiming to enhance ambulation in the ward. This phase generally involves in-hospital exercises at a CR center with heart rate (HR) and electrocardiogram (ECG) monitoring. Phase 2 represents the early stage of outpatient CR, which typically occurs within 1–3 months after a cardiac operation. In phase 3, patients actively engage in home- and community-based CR exercises and risk factor management, allowing them to sustain lifelong follow-up care in their homes and local communities [ 7 ]. Before starting phase 2 CR, typically approximately 4 weeks postoperatively, patients undergo a cardiopulmonary exercise test (CPET). Those categorized as having a moderate-to-high risk of cardiac arrest during exercise are advised to engage in center-based CR (CBCR). However, participation rates in CBCR remain suboptimal, with approximately 30% of eligible patients participating worldwide. This low participation rate can be attributed to challenges, such as limited center accessibility, geographical distance, financial constraints, and time constraints [ 8 ]. In South Korea, the implementation rate of CBCR stands at only 28%, lower than the global average (12% in secondary medical centers and 41% in tertiary centers), primarily due to a shortage of staff and space [ 9 ]. Moreover, following the World Health Organization’s declaration of the pandemic caused by the new coronavirus, SARS-CoV-2, the participation rate in CBCR further decreased [ 10 ]. Home-based CR (HBCR) has been introduced as an alternative to CBCR to improve participation. According to a 2019 Cochrane review, both HBCR and CBCR demonstrated comparable effects on clinical outcomes and quality of life among individuals with heart failure and acute coronary syndrome [ 11 ]. With the improvement of telemedicine, HBCR using remote monitoring devices are increasingly prevalent. By monitoring patients’ objective data, such as HR, ECG, and physical activity, individuals can safely engage in exercise programs, leading to a reduction in anxiety [ 12 – 17 ]. Studies have found that an early initiation of CR following cardiac surgery not only reduces mortality and shortens hospital stays but also, importantly, does not lead to an increase in adverse events [ 18 , 19 ]. However, to our knowledge, majority of previous studies on HBCR with remote monitoring have been conducted at least 1 month after surgery or discharge. Consequently, studies exploring the safety and effectiveness of home-based telerehabilitation within the first month following open-heart surgery are lacking. Therefore, we aimed to evaluate the safety and feasibility of an early CR program using remote ECG monitoring during an early postoperative period in patients who underwent cardiac surgery. Methods Study population This was a single-center prospective study that included patients who underwent open-heart surgery at the OO Hospital. The Institutional Review Board of OO Hospital approved the study design (approval no: 2021AN0089). Between November 2021 and April 2023, patients who underwent open-heart surgery and were referred to the Rehabilitation Medicine Department for inpatient CR were screened for eligibility. Patients were included in the study if they were aged > 18 years, had a left ventricular ejection fraction > 35.0%, were capable of performing an exercise test, were able to comprehend instructions related to a mobile application and ECG monitoring patch used during the trial, and were able to ambulate independently. Informed consent was obtained from all the participants before enrollment. Exclusion criteria encompassed individuals with a history of cardiac arrest or those with an implantable cardioverter-defibrillator, unstable vital signs, cognitive impairment preventing understanding of the exercise protocol and instructions, lower extremity musculoskeletal or neurological diseases complicating exercise training, or those unable to ambulate independently. Study protocol On average, 5 d postoperatively, the participants initiated a low-intensity inpatient CR program while wearing an ECG monitoring device. Before starting the program, baseline data, including grip strength (GS), 6-min walk distance (6 MWD), EuroQol-5 dimension (EQ-5D), short-form 36-item health survey (SF-36), and Korean Activity Scale/Index (KASI), were collected. Outcomes were measured at three time points: starting CR (average 5 d postoperatively) (T1), before discharge from the hospital (approximately 9 d postoperatively) (T2), and at the end of the study period (approximately 3–4 weeks postoperatively) (T3). The exercise stress test and squat endurance test were conducted at two points: T2 and T3 (Fig. 1). Before starting the exercise program, the patients were instructed on proper utilization of the ECG patch monitor and mobile applications. They were advised to wear the patches consistently throughout the study period. The inpatient CR program was conducted five times a week for a total of 1 h. The program consisted of a 10-min warm-up exercise, 10-min of resistance training, 30 min of aerobic exercise, and a 10-min cool-down phase. If the patient experienced dyspnea during the exercise, a brief rest period was encouraged before resuming the program. Before discharge, approximately 9 d postoperatively, the patients underwent a symptom-limited submaximal exercise test using an ergometer and squat endurance test. These assessments were aimed at determining the appropriate intensity and target HR for subsequent home-based aerobic and strength exercises. For the incremental symptom-limited exercise test, subjects lay on a cycle ergometer (Corival Recumbent cpet 969900, Lode, Groningen, Netherlands) (Fig. 2) and pedaled the bicycle with an initial load of 0 watts and pedaling frequency of 60 rpm, and the workload was increased by 20 watts every 2 min. The test was terminated if any absolute indications for discontinuation during the examination were observed or if pre-established termination criteria were met (Table 1 ). During the test, HR, peak oxygen consumption, peak metabolic equivalent of task (MET), maximal work capacity (Wmax), peak respiratory exchange ratio, peak rate of perceived exertion (RPE), peak dyspnea scale, peak angina scale, and total exercise duration were measured. Metabolic equivalent of task was automatically calculated, with one MET defined as the oxygen consumption level during seated rest (equivalent to 3.5 mL of oxygen per kg per min) [ 20 ]. The Wmax was determined by the highest intensity that an individual can sustain for 30 s, beyond which it becomes unsustainable. Following 2 weeks of home-based exercise, the patients revisited the hospital for a follow-up exercise test. The test was conducted on a treadmill instead of a cycle ergometer. A squat endurance test [ 21 ] was conducted to assess the intensity of the targeted resistance exercise. The participants leaned against the wall, stood with their feet shoulder-width apart, and initiated squats by flexing their knees at a 90 ° angle from a standing position. The test was performed with the intensity set between 40– 60% of the HR reserve, determined through symptom-limited submaximal exercise testing, and continued until it reached a slightly challenging level (RPE 13). After discharge, the patients underwent a 2-week HBCR program. For aerobic exercises, the patients were informed of their target HR using the Karvonen formula [ 22 ], with an exercise intensity set at 40–55% of the HR reserve determined from an incremental submaximal exercise test. The target HR can be estimated as follows: (target HR = resting HR + [0.40 − 0.55] × [peak HR − resting HR]). Since all the patients maintained their HRs within the target range (40–60% of peak HR) when reaching RPE 13, we recommended that they perform the same number of squat repetitions for their home exercise. Remote ECG monitoring system To monitor remote ECG data, we used MEMO Patch (MEMO Patch, HUINNO Co., Ltd., Seoul, South Korea) (Fig. 3), the first ambulatory ECG device approved by the Korean Food and Drug Administration. This adhesive single-lead patch can store ECG data for up to 14 d. A cohort study in Korea showed that using the patch for 7-d continuous ECG monitoring was more effective in detecting supraventricular tachycardia than the traditional 24-h Holter monitor [ 23 ]. The recorded ECG data from the patch was subjected to analysis using MEMO Artificial intelligence (AI), which was constructed and trained by HUINNO for arrhythmia classification [ 24 ]. The AI algorithm employed in this study integrates multiple components tailored for specific tasks within cardiac signal analysis. First, it uses a convolutional neural network architecture with skip connections engineered specifically to detect episodic arrhythmias and filter out noise signals, enhancing the reliability of detection. Second, a dedicated segmentation and classification network was implemented, which was finely tuned to identify and delineate the P, QRS, and T segments of the ECG, enabling detailed feature extraction from these critical signal components. Finally, a sophisticated postprocessing algorithm synthesizes the information from the previous stages to refine the overall analysis. This multifaceted approach ensures a robust and precise initial analysis by leveraging deep learning techniques to improve diagnostic accuracy. After the ECG data were analyzed using AI, the technicians manually reviewed and verified the AI-generated diagnosis. If necessary, the diagnosis was revised after confirmation by cardiologists. The patients were instructed to wear the patch consistently throughout the study period. In addition, they were provided with mobile phones featuring internet connectivity, and the device was preloaded with an application connected to the ECG patch. During the daily exercise, the patients activated the application to transmit their ECG data, and upon completion, they deactivated the application. Subsequently, the ECG data were transmitted in real-time to the HUINNO Cloud. Medical doctors closely monitored the data using the MEMO Care website and provided feedback to the patients through telephone calls (Fig. 4). If ventricular fibrillation, sustained ventricular tachycardia, or ST segment elevation > 1 mm was observed in the ECG data, the researchers planned to recommend discontinuing home-based exercises and scheduling an earlier hospital visit via telephone calls. Additionally, the patients were instructed to report “patients triggered events” by pressing the button on the patch if they experienced angina chest pain, dizziness, or syncope. At the end of each week, the participants visited the hospital to return the patch, where doctors offered further guidance by reviewing the weekly reports available on the website. The weekly report covers the entire monitoring period and includes data on minimum, average, and maximum HRs, as well as details on the number and duration of various arrhythmia events, such as atrial fibrillation (AF), supraventricular tachycardia, ventricular fibrillation, atrial premature complexes, ventricular premature complexes, and patient-triggered events (Fig. 5). After the study period, the participants completed a 14-item self-report questionnaire on their satisfaction with the ECG patch. Physical assessments GS The GS test is a widely employed method for assessing muscle strength and serves as a predictor of various health outcomes, including cardiovascular mortality, length of hospital stay, functional status, and perioperative complications [ 25 – 27 ]. To assess GS, the participants were instructed to apply maximal force alternately with their left and right hands on a handheld dynamometer (JAMAR PLUS + Digital Hand Dynamometer; Sammons Preston Rolyan, Bolingbrook, IL, USA ) and repeat this process twice. Following two attempts, maximal grip power (kg) was recorded. The greater GS between the two hands was used for further analysis. 6 MWD The 6 MWD is a simple and safe test that has been found to significantly reflect functional status and activities of daily living [ 28 ]. The participants were instructed to walk along a 30-m corridor for 6 min, aiming to cover as much distance as possible while maintaining a perceived intensity between three (moderate) and four (somewhat strong) on the Borg CR scale (CR 10) [ 29 ]. Rest was permitted if participants felt exhausted, and the test was halted if they experienced dyspnea or chest pain that impeded daily activities. Elapsed time was recorded for the patients at each minute of assessment without additional feedback or encouragement. Oxygen saturation, blood pressure, and HR were measured before and after the test, and the distance covered during the 6-min period was recorded. Self-reported survey SF-36 The SF-36 is a widely used self-reported quality-of-life questionnaire consisting of 36 items. It assesses physical health using physical function, physical role, bodily pain, and general health. Additionally, it evaluates mental health using vitality, social function, role emotional, and mental health. These eight subscales were further divided into 35 items, with the remaining one addressing health change perception, for a total of 36 detailed items. Assigning scores to the detailed items within each of the eight subscales and adding them yields a total score ranging from 0 (indicating the poorest health) to 100 (indicating the best health). The scores can be summarized into two main areas: the physical component summary (PCS) and mental component summary (MCS). In the general population, scores for each component are expected to have a mean of 50 and standard deviation of 10 [ 30 ]. We used the Korean version of the questionnaires to ensure that patients can easily comprehend and complete the test [ 31 ]. KASI The Korean Activity Scale/Index (KASI) [ 32 ] is a Korean-translated version of the Duke Activity Status Index, which is a 12-item scale survey designed to assess functional capacity and quality of life. This test demonstrated a significant correlation between peak oxygen uptake [ 33 ] and the occurrence of major adverse cardiac events [ 34 ]. The participants were asked to self-assess the questionnaires, and the total scores were determined based on their responses. EQ-5D The EQ-5D was used to assess health-related quality of life in our study [ 35 ]. It consists of five dimensions of questions about current health state (mobility, self-care, and usual activities), which comprises five dimensions concerning current health status (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), with each dimension consisting of a three-point scale (no problem, moderate problem, and severe problems). Responses to each question were transformed into final scores using Korean value set calculations, ranging between − 0.171 and 1. A score of 1 indicates a “healthy state without problems,” while a score of 0 represents “death,” and scores below 0 indicate a state “worse than death.” [ 36 , 37 ]. Statistical analysis Statistical analyses were performed using IBM SPSS Statistics for Windows version 26. To compare baseline characteristics between CABG and non-CABG groups, the Student’s t-test was used for continuous variables, while the chi-square test was used for categorical variables. A mixed linear model with an unstructured covariance matrix was used to analyze changes in repeatedly measured primary and secondary outcomes over time. The model incorporated covariates, such as time, group, 6 MWD, EQ-5D, SF-36, KASI, squat endurance test, and measurements obtained using submaximal exercise tests. Statistical significance was considered at p < 0.05. Results Baseline characteristics Baseline demographics and disease-related characteristics of the participants are summarized in Table 2 . Of the 22 patients enrolled in the study, six dropped out during the follow-up period. Three patients withdrew from the study due to an inability to maintain continuous observation, as they did not routinely wear the monitoring device or adhere to the study protocol. Two patients were excluded because they were diagnosed with COVID-19. One patient discontinued participation due to poor general health. Sixteen patients, with an average age (standard deviation) of 63.38 (1.89) years, successfully completed the study, and twelve (75.0%) of them were males. Median (interquartile range [IQR] ) time to the initiation of CR was 5 (5–6) d. Among the participants, seven (43.8%) underwent CABG, seven (43.8%) underwent valve replacement surgery, one underwent total arch replacement surgery (6.3%), and one received coronary artery fistulectomy (6.3%). Comparison between patients who underwent CABG and those who underwent non-CABG surgery showed no significant differences ( p > 0.05). Changes over time in participants outcomes Comparison between the second assessment at T2 and final assessment at T3 (T2-T3) showed that peak VO 2 increased from 12.39 ± 0.57 mL/kg/min to 17.93 ± 1.25 mL/kg/min ( p < 0.01), peak MET improved from 3.54 ± 0.28 mL/kg/min to 5.11 ± 0.28 mL/kg/min ( p < 0.01), and peak HR increased from 110.19 ± 5.53 to 122.12 ± 5.53 ( p < 0.01). Additionally, the squat endurance test demonstrated improvement from 16.69 ± 2.31 to 21.81 ± 2.31 ( p < 0.01). Compared to the initial assessment at T1, the GS showed improvement from 28.30 ± 1.66 kg to 30.40 ± 1.70 kg at T3 ( p = 0.02). However, no significant change was noted between T2 (30.62 ± 1.68 kg) and T3. The 6 MWD increased from 249.33 ± 20.92 m at T1 to 387.02 ± 22.77 m at T3 ( p < 0.01). The EQ-5D scores improved from 0.59 ± 0.03 at T1 to 0.82 ± 0.03 at T3. The KASI improved from 5.44 ± 0.58 at T1 to 26.11 ± 2.70 at T3 ( p < 0.01). Total scores of the SF-36 showed improvement from 83.99 ± 3.40 at T1 to 122.82 ± 6.06 at T3 ( p < 0.01). The PCS of SF-36 significantly improved from 32.16 ± 1.55 at T1 to 57.69 ± 3.20 at T3 ( p < 0.01). Although the MCS score showed a significant increase ( p = 0.002) between T1 (51.83 ± 2.59) and T3 (64.15 ± 3.02), no significant difference was noted between T2 and T3 (p = 0.09) (Fig. 6). In the subgroup analysis, the CABG group demonstrated a greater increase in 6 MWD (102.29 m, p < 0.01) than the non-CABG group. However, no significant differences were observed in other measurements between the two groups. ECG recording results Between time points T1 and T3, the average duration of ECG monitoring increased from 125 hours to 179 hours. The median occurrence of atrial premature complex changed from 261 to 155, while that of ventricular premature complex decreased from 135 to 88.5. Atrial fibrillation was reported in five patients, and nonsustained ventricular tachycardia events were reported in six patients. Adverse effects Regarding safety concerns, there were no reported serious adverse events, such as hospitalization, cardiac arrest, or death. Throughout the study period, no instances of sustained ventricular tachycardia or fibrillation were recorded using an ECG monitoring device. Patient satisfaction regarding the remote monitoring-based HBCR program Based on the final self-report questionnaires, 12 (75.0%) patients completed the HBCR program with satisfactory remote ECG monitoring. Participants primarily expressed satisfaction because they felt reassured by the real-time HR monitoring through the mobile application (75.0%) and because they were able to review the automatically saved ECG records later (68.8%). Additionally, they appreciated their ability to regulate exercise intensity with alarms set above individual HR thresholds. In terms of areas that needed improvement, four (25.0%) patients reported experiencing a skin rash and itching sensation at the patch attachment site. Three (18.8%) patients mentioned that the patch detached easily when sweating occurred after the exercise. Two (12.5%) patients reported Bluetooth disconnection. Additionally, three (18.8%) patients, with an average age of 73.3 years, encountered difficulties in manipulating the mobile application due to their advanced age. Discussion The principal finding of this study was that initiating early CR within 1 month after the first-time open-heart surgery, using an ECG monitoring device, resulted in significant improvements in exercise capacity, quality of life, and various functional outcomes. To the best of our knowledge, the present study is the first to validate the safety and effectiveness of initiating early rehabilitation using a remote ECG device coupled with real-time feedback among patients undergoing different cardiac surgeries, such as CABG, valve operations, and aortic surgeries. Previous studies using ECG monitoring systems for remote postopen-heart surgery monitoring primarily began exercise programs during the phase II period [ 16 , 38 , 39 ], with a lack of studies initiating home exercise programs within 2 weeks postoperatively [ 40 ]. Even though all patients who undergo open-heart surgery are recommended to receive CR, the CR participation rate remains suboptimal [ 9 ]. Home-based exercise training with a telemonitoring system could serve as an effective alternative model to achieve this objective. Previous studies have indicated that telerehabilitation with various monitoring systems has a comparable effect to hospital-based rehabilitation [ 12 , 41 – 43 ]. Recent CR guidelines advocate for ECG-monitored exercise during an early postonset period [ 5 , 44 ]. An ECG monitoring system, capable of recording one-lead cardiac rhythm, detecting arrhythmias, and monitoring HR, can enhance adherence to CR. In our study, we observed a notable increase in the total duration of patients wearing the ECG-monitoring device over a span of approximately 3 weeks. Additionally, receiving real-time feedback from the medical team instills confidence and a sense of safety among patients, thereby further improving their participation rate. Although our study only included an intervention group without a control group that did not participate in the exercise program, our results showed improvements in various exercise parameters (peak VO 2 , MET, and peak HR) during incremental exercise tests after 2 weeks of home-based exercise programs. These findings support previous reports highlighting that telerehabilitation offers benefits comparable to standard rehabilitation therapy [ 15 , 45 – 47 ]. Additionally, the total KASI and EQ-5D scores, which indicate the patient’s activity levels and quality of life, showed a significant increase compared to the initial assessment and discharge. As KASI scores are known to correlate with oxygen capacity [ 33 ], it suggests that the program plays a role in enhancing cardiovascular function. Similarly, the total SF-36 score significantly increased after 2 weeks of CR. The PCS measures of the SF-36 demonstrated significant improvement in the final test compared with the initial assessment and discharge status. However, only the MCS measures of SF-36 showed a significant change between the final and initial measurements. No significant differences were observed between the final follow-up and discharge statuses. These improvements signify that despite the burden of open-heart surgery, the participants demonstrated significant enhancements in physical function and overall quality of life after completing the 2-week exercise program. From a safety perspective, conducting HBCR with remote monitoring shortly after open-heart surgery, within 2-weeks postoperation, did not increase the risk of postoperative adverse events. Atrial fibrillation is the most common complication after cardiac surgery, occurring in 15.0–40.0% of cases after CABG and 37.0–50.0% after valve surgery [ 48 ]. Nonsustained ventricular arrhythmias are reported in up to 36.0% of cases [ 49 ], whereas sustained ventricular arrhythmias occur in 0.4–1.4% of cases after cardiac surgery [ 50 ]. In our study, AF was detected in five (31.3%) patients, while nonsustained ventricular tachycardia was observed in six (37.5%). Among them, four patients experienced AF for the first time postoperatively during a remote ECG-monitoring exercise training session. However, the duration of AF in these cases was brief, ranging between 6–10 min. Throughout the training session, none of the participants experienced life-threatening events, such as sustained ventricular tachycardia or ventricular fibrillation. Furthermore, no instances of patients being readmitted to the hospital or emergency department were noted during the program. Ennis et al. observed that commencing exercise training as early as 2 weeks after sternotomy enhances functional outcomes and the 6 MWD sooner [ 51 ]. This early intervention allows patients to regain social function and economic productivity earlier, contributing to an improved quality of life without any substantial additional risks. Consequently, the patients were able to achieve aerobic exercise capacity sooner, potentially leading to earlier improvements in functional activity. However, in Korea, exercise therapy is still postponed for 4 weeks owing to general condition and suture site concerns following cardiac surgery [ 5 , 52 , 53 ]. Our findings suggest that initiating remote ECG-monitoring-based HBCR within 2 weeks postoperatively can be safely implemented in patients who have recently undergone cardiac surgery. Through feedback gathered from patient surveys, we identified key areas for enhancing the effectiveness of remote CR. A smartphone application integrated with an ECG monitoring system has great potential for HBCR programs [ 54 ]. However, to encourage broader usage, ensuring that patients can easily use both the application and device is crucial. In our study, 18.8% of the participants reported difficulties with the mobile application. Given that many cardiac surgery patients are older and less familiar with mobile technology, simplifying procedures, such as device application and removal, as well as app navigation, is essential. Additionally, 12.5% of patients faced challenges with Bluetooth connectivity, emphasizing the need to improve internet stability for broader and safer adoption of telerehabilitation. Moreover, addressing skin issues is crucial as participants cannot readily access advice or patch-exchange services while engaging in home-based exercises. Therefore, improving patches is essential for alleviating attachment problems and skin irritation. Limitation This study has several important limitations. First, the absence of a control group that did not receive exercise training made it challenging to accurately gauge the true effect of CR on functional outcomes and aerobic capacity. Second, majority of the participants were males aged 50–70 years, and because of the small sample size, generalizing the study findings is difficult. Third, the initial submaximal exercise test used a cycle ergometer to minimize the burden on patients, whereas the follow-up test employed a treadmill. This discrepancy may have introduced heterogeneity into the final measurements. Fourth, since the final measurements were conducted about 3–4 weeks postoperatively, there were no long-term follow-up results regarding functional outcomes or aerobic capacity. In the future, a large-scale randomized controlled trial with long-term follow-up is warranted to validate the findings of our study. Conclusion The findings of this study suggest that starting HBCR exercise training within 1 month after cardiac surgery, combined with remote ECG monitoring, leads to beneficial outcomes for aerobic capacity, functional status, and quality of life. No significant adverse events were reported during the study period. These results provide valuable insights for clinicians, enabling them to confidently design HBCR with ECG monitoring within the first month after an open heart surgery. Further studies on CR programs using various wearable devices capable of tracking diverse physical activities of patients, including ECG monitoring, is necessary for continued advancement. Abbreviations CABG coronary artery bypass grafting CR cardiac rehabilitation HR heart rate ECG electrocardiogram CPET cardiopulmonary exercise test CBCR center-based cardiac rehabilitation HBCR home-based cardiac rehabilitation GS grip strength 6MWD 6-min walk distance EQ-5D EuroQol-5 dimension SF-36 short-form 36-item health survey PCS Physical component summary MCS Mental component summary KASI Korean Activity Scale/Index MET metabolic equivalent of task Wmax maximal work capacity RPE rate of perceived exertion Declarations Ethics approval and consent to participate Study procedures were approved by the the Institutional Review Board of Korea University Anam Hospital (approval no: 2021AN0089). Written informed consent was obtained from patients. For illiterate patients, informed consent was obtained from the patient’s legal guardian. Consent for publication We obtained written informed consent for the publication of the individual’s data and image included in the manuscript. Competing interests The authors declare no competing interests. Funding The authors received no financial support for the research, authorship, and/or publication of this article Author contributions All authors contributed to the study design and approval of the final version of the table. Yeon Mi Kim, M.D.: Writing - Original Draft, Formal Analysis, Investigation, Validation, Resources. Bo Ryun Kim, M.D., Ph.D.: Conceptualization, Methodology, Formal Analysis, Investigation, Writing - Review & Editing, Funding Acquisition . Sung Bom Pyun, M.D., Ph.D.: Project Administration, Writing - Review & Editing, Supervision. Jae Seung Jung, M.D., Ph.D.: Investigation, Resources, Writing - Review & Editing, Hee Jung Kim, M.D., Ph.D.: Resources, Validation, Writing - Review & Editing, Ho Sung Son, M.D., Ph.D.: Project Administration, Resources, Writing - Review & Editing, Supervision. Acknowledgements This research was supported by a Korea University Grant. 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Turk J Phys Med Rehabil. 2022;68:317-35. https://doi.org/10.5606/tftrd.2022.11435. Buckingham SA, Taylor RS, Jolly K, Zawada A, Dean SG, Cowie A, et al. Home-based versus centre-based cardiac rehabilitation: abridged Cochrane systematic review and meta-analysis. Open Heart. 2016;3:e000463. https://doi.org/10.1136/openhrt-2016-000463. Milewski K, Małecki A, Orszulik-Baron D, Kachel M, Hirnle P, Orczyk M, et al. The use of modern telemedicine technologies in an innovative optimal cardiac rehabilitation program for patients after myocardial revascularization: Concept and design of RESTORE, a randomized clinical trial. Cardiol J. 2019;26:594-603. https://doi.org/10.5603/CJ.a2018.0157. Kikuchi A, Taniguchi T, Nakamoto K, Sera F, Ohtani T, Yamada T, et al. Feasibility of home-based cardiac rehabilitation using an integrated telerehabilitation platform in elderly patients with heart failure: A pilot study. J Cardiol. 2021;78:66-71. https://doi.org/10.1016/j.jjcc.2021.01.010. Bravo-Escobar R, González-Represas A, Gómez-González AM, Montiel-Trujillo A, Aguilar-Jimenez R, Carrasco-Ruíz R, et al. Effectiveness and safety of a home-based cardiac rehabilitation programme of mixed surveillance in patients with ischemic heart disease at moderate cardiovascular risk: A randomised, controlled clinical trial. BMC Cardiovasc Disord. 2017;17:66. https://doi.org/10.1186/s12872-017-0499-0. Ramachandran HJ, Jiang Y, Tam WWS, Yeo TJ, Wang W. Effectiveness of home-based cardiac telerehabilitation as an alternative to Phase 2 cardiac rehabilitation of coronary heart disease: a systematic review and meta-analysis. Eur J Prev Cardiol. 2022;29:1017-43. https://doi.org/10.1093/eurjpc/zwab106. Scalvini S, Zanelli E, Comini L, Dalla Tomba M, Troise G, Febo O, et al. Home-based versus in-hospital cardiac rehabilitation after cardiac surgery: a nonrandomized controlled study. Phys Ther. 2013;93:1073-83. https://doi.org/10.2522/ptj.20120212. Nishitani-Yokoyama M, Shimada K, Fujiwara K, Abulimiti A, Kasuya H, Kunimoto M, et al. Safety and Feasibility of Tele-Cardiac Rehabilitation Using Remote Biological Signal Monitoring System: A Pilot Study. Cardiol Res. 2023;14:261-7. https://doi.org/10.14740/cr1530. Sezai A, Shimokawa T, Kanaoka K, Fukuma N, Sekino H, Shiraishi H, et al. Efficacy of Early Cardiac Rehabilitation After Cardiac Surgery - Verification Using Japanese Diagnosis Procedure Combination Data. Circ Rep. 2022;4:505-16. https://doi.org/10.1253/circrep.CR-22-0088. Pack QR, Dudycha KJ, Roschen KP, Thomas RJ, Squires RW. Safety of early enrollment into outpatient cardiac rehabilitation after open heart surgery. Am J Cardiol. 2015;115:548-52. https://doi.org/10.1016/j.amjcard.2014.11.040. Franklin BA, Brinks J, Berra K, Lavie CJ, Gordon NF, Sperling LS. Using Metabolic Equivalents in Clinical Practice. Am J Cardiol. 2018;121:382-7. https://doi.org/10.1016/j.amjcard.2017.10.033. Haramura M, Takai Y, Yoshimoto T, Yamamoto M, Kanehisa H. Cardiorespiratory and metabolic responses to body mass-based squat exercise in young men. J Physiol Anthropol. 2017;36:14. https://doi.org/10.1186/s40101-017-0127-9. Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn. 1957;35:307-15. Kim JY, Oh IY, Lee H, Lee JH, Cho Y, Gil Y, et al. The efficacy of detecting arrhythmia is higher with 7-day continuous electrocardiographic patch monitoring than with 24-h Holter monitoring. J Arrhythm. 2023;39:422-9. https://doi.org/10.1002/joa3.12865. Kim S, Lim J, Shin M, Jung S. SE-ResNet-ViT Hybrid Model for Noise Classification in Adhesive Patch-type Wearable Electrocardiographs. Annu Int Conf IEEE Eng Med Biol Soc. 2023;2023:1-4. https://doi.org/10.1109/embc40787.2023.10340882. Bohannon RW. Hand-grip dynamometry predicts future outcomes in aging adults. J Geriatr Phys Ther. 2008;31:3-10. https://doi.org/10.1519/00139143-200831010-00002. Rantanen T, Guralnik JM, Foley D, Masaki K, Leveille S, Curb JD, et al. Midlife hand grip strength as a predictor of old age disability. JAMA. 1999;281:558-60. https://doi.org/10.1001/jama.281.6.558. Fu L, Zhang Y, Shao B, Liu X, Yuan B, Wang Z, et al. Perioperative poor grip strength recovery is associated with 30-day complication rate after cardiac surgery discharge in middle-aged and older adults - a prospective observational study. BMC Cardiovasc Disord. 2019;19:266. https://doi.org/10.1186/s12872-019-1241-x. Enright PL. The six-minute walk test. Respir Care. 2003;48:783-5. Borg GA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc. 1982;14:377-81. Ware JE, Jr. SF-36 health survey update. Spine (Phila Pa 1976). 2000;25:3130-9. https://doi.org/10.1097/00007632-200012150-00008. Han CW, Lee EJ, Iwaya T, Kataoka H, Kohzuki M. Development of the Korean version of Short-Form 36-Item Health Survey: health related QOL of healthy elderly people and elderly patients in Korea. Tohoku J Exp Med. 2004;203:189-94. https://doi.org/10.1620/tjem.203.189. Sung J, On YK, Kim HS, Chae IH, Sohn DW, Oh BH, et al. Development of Korean activity scale/index (KASI). Korean Circ J. 2000;30:1004-9. Hlatky MA, Boineau RE, Higginbotham MB, Lee KL, Mark DB, Califf RM, et al. A brief self-administered questionnaire to determine functional capacity (the Duke Activity Status Index). Am J Cardiol. 1989;64:651-4. https://doi.org/10.1016/0002-9149(89)90496-7. Shaw LJ, Olson MB, Kip K, Kelsey SF, Johnson BD, Mark DB, et al. The value of estimated functional capacity in estimating outcome: results from the NHBLI-Sponsored Women's Ischemia Syndrome Evaluation (WISE) Study. J Am Coll Cardiol. 2006;47:S36-S43. https://doi.org/10.1016/j.jacc.2005.03.080. Rabin R, de Charro F. EQ-5D: a measure of health status from the EuroQol Group. Ann Med. 2001;33:337-43. https://doi.org/10.3109/07853890109002087. Kim MH, Cho YS, Uhm WS, Kim S, Bae SC. Cross-cultural adaptation and validation of the Korean version of the EQ-5D in patients with rheumatic diseases. Qual Life Res. 2005;14:1401-6. https://doi.org/10.1007/s11136-004-5681-z. Nam HS. EQ‐5D Korean valuation study using time trade of method. Seoul: Korea Centers for Disease Control and Prevention. 2007. Wolszakiewicz J, Piotrowicz E, Foss-Nieradko B, Dobraszkiewicz-Wasilewska B, Piotrowicz R. A novel model of exercise walking training in patients after coronary artery bypass grafting. Kardiol Pol. 2015;73:118-26. https://doi.org/10.5603/KP.a2014.0165. Vongvanich P, Bairey Merz CN. Supervised exercise and electrocardiographic monitoring during cardiac rehabilitation. Impact on patient care. J Cardiopulm Rehabil. 1996;16:233-8. https://doi.org/10.1097/00008483-199607000-00004. Scalvini S, Zanelli E, Comini L, Tomba MD, Troise G, Giordano A. Home-based exercise rehabilitation with telemedicine following cardiac surgery. J Telemed Telecare. 2009;15:297-301. https://doi.org/10.1258/jtt.2009.090208. Ades PA, Pashkow FJ, Fletcher G, Pina IL, Zohman LR, Nestor JR. A controlled trial of cardiac rehabilitation in the home setting using electrocardiographic and voice transtelephonic monitoring. Am Heart J. 2000;139:543-8. https://doi.org/10.1016/s0002-8703(00)90100-5. Piotrowicz E, Baranowski R, Bilinska M, Stepnowska M, Piotrowska M, Wójcik A, et al. A new model of home-based telemonitored cardiac rehabilitation in patients with heart failure: effectiveness, quality of life, and adherence. Eur J Heart Fail. 2010;12:164-71. https://doi.org/10.1093/eurjhf/hfp181. Lee Y, Lee J, Seo H, Kim K, Min D, Lee J, et al. Effects of Home-based Exercise Training with Wireless Monitoring on the Left Ventricular Function of Acute Coronary Syndrome Patients. J Phys Ther Sci. 2013;25:631-3. https://doi.org/10.1589/jpts.25.631. Wenger NK. Current status of cardiac rehabilitation. J Am Coll Cardiol. 2008;51:1619-31. https://doi.org/10.1016/j.jacc.2008.01.030. Milewski K, Balsam P, Kachel M, Sitek B, Kolarczyk-Haczyk A, Skoczyński S, et al. Actual status and future directions of cardiac telerehabilitation. Cardiol J. 2023;30:12-23. https://doi.org/10.5603/CJ.a2022.0104. Huang K, Liu W, He D, Huang B, Xiao D, Peng Y, et al. Telehealth interventions versus center-based cardiac rehabilitation of coronary artery disease: A systematic review and meta-analysis. Eur J Prev Cardiol. 2015;22:959-71. https://doi.org/10.1177/2047487314561168. Hwang R, Bruning J, Morris N, Mandrusiak A, Russell T. A Systematic Review of the Effects of Telerehabilitation in Patients With Cardiopulmonary Diseases. J Cardiopulm Rehabil Prev. 2015;35:380-9. https://doi.org/10.1097/hcr.0000000000000121. Boons J, Van Biesen S, Fivez T, de Velde MV, Al Tmimi L. Mechanisms, Prevention, and Treatment of Atrial Fibrillation After Cardiac Surgery: A Narrative Review. J Cardiothorac Vasc Anesth. 2021;35:3394-403. https://doi.org/10.1053/j.jvca.2020.11.030. Yeung-Lai-Wah JA, Qi A, McNeill E, Abel JG, Tung S, Humphries KH, et al. New-onset sustained ventricular tachycardia and fibrillation early after cardiac operations. Ann Thorac Surg. 2004;77:2083-8. https://doi.org/10.1016/j.athoracsur.2003.12.020. Chung MK. Cardiac surgery: postoperative arrhythmias. Crit Care Med. 2000;28:N136-N44. https://doi.org/10.1097/00003246-200010001-00005. Ennis S, Lobley G, Worrall S, Evans B, Kimani PK, Khan A, et al. Effectiveness and Safety of Early Initiation of Poststernotomy Cardiac Rehabilitation Exercise Training: The SCAR Randomized Clinical Trial. JAMA Cardiol. 2022;7:817-24. https://doi.org/10.1001/jamacardio.2022.1651. Maines TY, Lavie CJ, Milani RV, Cassidy MM, Gilliland YE, Murgo JP. Effects of cardiac rehabilitation and exercise programs on exercise capacity, coronary risk factors, behavior, and quality of life in patients with coronary artery disease. South Med J. 1997;90:43-9. https://doi.org/10.1097/00007611-199701000-00010. Kim C, Sung J, Han JY, Jee S, Lee JW, Lee JH, et al. Current Status of Cardiac Rehabilitation in the Regional Cardiocerebrovascular Centers in Korea. J Clin Med. 2021;10:5079. https://doi.org/10.3390/jcm10215079. Worringham C, Rojek A, Stewart I. Development and feasibility of a smartphone, ECG and GPS based system for remotely monitoring exercise in cardiac rehabilitation. PLoS One. 2011;6:e14669. https://doi.org/10.1371/journal.pone.0014669. Tables Table 1. Termination criteria for the symptom-limited submaximal exercise tests Absolute indication for stop test Pre-established termination criteria - ST-segment elevation >1 mm without abnormal Q waves in the ECG channels, excluding V1 and aVR - Decrease in SBP >10 mmHg or a drop below resting SBP - Severe or higher-grade angina (Angina scale Grade 3–4) - Able to ambulate without physical assistance - Exacerbation of neurological symptoms (e.g., dizziness and ataxia) - Cyanosis or pallor - Persistent ventricular tachycardia - Patient's desire to discontinue the test - HR >120 beats per minute. - Reaching 70% of the maximum predicted heart rate based on the patient’s age. - Achieving a predetermined MET level (typically 5–7). - Uncontrolled medical condition - RPE (rate of perceived exertion) exceeds 15 on the Borg 6–20 grade scale. SBP, systolic blood pressure; HR, heart rate; MET, metabolic equivalent of task Table 2 . Baseline clinical characteristics and initial 6 MWD, EQ5D, KASI, and SF36 results (N=16) Variables Subgroup analysis Total (N=16) CABG (N=7) Non-CABG (N=9) P-value Age (years) 63.38 ± 1.89 64.43 ± 7.35 62.56 ± 8.03 0.639 Sex, males/females 12 (75)/4 (25) 12 (86)/1 (14) 6 (67)/3 (33) 0.536 Height (cm) 164.63 ± 2.19 164.33 ± 8.01 166.63 ± 9.62 0.618 Weight (kg) 66.23 ± 2.40 67.71 ± 6.56 65.08 ± 11.73 0.604 Body mass index (kg/m 2 ) 24.05 ± 0.56 25.04 ± 1.31 23.28 ± 2.54 0.096 Time to start cardiac rehabilitation (days) 5.00 (5.00; 6.00) 5.00 (4.00; 6.00) 6.00 (5.00; 6.00) 0.174 Grip strength test (kg) 28.19 ± 1.82 28.24 ± 6.83 28.04 ± 8.03 0.959 6 minute walk distance (m) 262.00 ± 21.04 237.57 ± 43.06 281.00 ± 104.69 0.283 Korean Activity Scale/Index (KASI) 4.90 (3.70;7.08) 4.90 (3.70;4.90) 6.70 (3.70;9.70) 0.174 EuroQol-5 dimension (EQ5D) 0.68 (0.51;0.68) 0.68 (0.47;0.68) 0.68 (0.51;0.70) 0.758 Short-form 36-item health survey (SF36) Total score 86.79 ± 4.14 84.82 ± 9.08 88.33 ± 21.12 0.689 Physical component summary (PCS) 33.61 ± 1.43 34.20 ± 3.55 33.16 ± 7.20 0.733 Mental component summery (MCS) 53.18 ± 3.26 50.63 ± 6.74 55.17 ± 16.56 0.471 Values represent mean ± standard deviation, median (interquartile range), or number (%) of cases. 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Lode, Groningen, Netherlands)\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4489270/v1/bc260fe6c459e636e745357e.jpg"},{"id":60447592,"identity":"eb4869f5-ddcf-40ac-bbb1-ec01aac6938c","added_by":"auto","created_at":"2024-07-16 22:04:49","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":327294,"visible":true,"origin":"","legend":"\u003cp\u003eMemo patch and attachment sites\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4489270/v1/a8310410a57fcbfc16b35e5e.jpg"},{"id":60447593,"identity":"da082f34-93ba-4153-bb57-3fc3f7c3b584","added_by":"auto","created_at":"2024-07-16 22:04:49","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":555650,"visible":true,"origin":"","legend":"\u003cp\u003eOverview of rehabilitation programs using remote monitoring devices\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4489270/v1/bd9c5eeebdd9d35a6dec4718.jpg"},{"id":60446760,"identity":"6e666bef-6872-4b37-85a0-c4c76a4ef8e1","added_by":"auto","created_at":"2024-07-16 21:56:49","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":338802,"visible":true,"origin":"","legend":"\u003cp\u003eExample of weekly artificial intelligence-generated report\u003c/p\u003e","description":"","filename":"Figure5..jpg","url":"https://assets-eu.researchsquare.com/files/rs-4489270/v1/86c086b2c30e76a3956b80c5.jpg"},{"id":60446757,"identity":"0ffb02bd-0302-45f5-8dcd-bd10755c2b03","added_by":"auto","created_at":"2024-07-16 21:56:49","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":151272,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in peak VO\u003csub\u003e2\u003c/sub\u003e (A), peak MET (B), peak HR (C), total exercise duration (D), squat endurance test (E), 6 MWD (F), GS (G), KASI (H), EQ-5D (I), and SF-36 (J, K, and L)\u003c/p\u003e","description":"","filename":"Figure6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4489270/v1/90a8de767dfbe888bc4ea2ae.jpg"},{"id":61104591,"identity":"b630bba3-90eb-49d1-9b80-4fcba614276d","added_by":"auto","created_at":"2024-07-25 15:50:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2921185,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4489270/v1/ac371713-bffa-409a-abd6-6736f6c2663b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Feasibility and safety of early cardiac rehabilitation using remote electrocardiogram monitoring in patients with cardiac surgery ","fulltext":[{"header":"Background","content":"\u003cp\u003eIn South Korea, a 25% increase in cardiovascular mortality was observed over the past decade, making it the second leading cause of death in 2022 [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Each year, approximately 10,000 patients are admitted to intensive care units following cardiovascular surgery, with a rising trend observed between 2010\u0026ndash;2019. Aortic surgery has demonstrated the highest mortality rate, followed by coronary artery bypass grafting (CABG) and valve surgery [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCardiac rehabilitation (CR) improves exercise capacity, quality of life, hospital admissions, and mortality rates. Clinical guidelines from Europe, America, and Korea strongly recommend the incorporation of CR for patients with congestive heart failure, valve disease, coronary heart disease, and postopen-heart surgery [\u003cspan additionalcitationids=\"CR4 CR5\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Cardiac rehabilitation comprises three phases. Phase 1 begins with early mobilization from intensive care units, aiming to enhance ambulation in the ward. This phase generally involves in-hospital exercises at a CR center with heart rate (HR) and electrocardiogram (ECG) monitoring. Phase 2 represents the early stage of outpatient CR, which typically occurs within 1\u0026ndash;3 months after a cardiac operation. In phase 3, patients actively engage in home- and community-based CR exercises and risk factor management, allowing them to sustain lifelong follow-up care in their homes and local communities [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBefore starting phase 2 CR, typically approximately 4 weeks postoperatively, patients undergo a cardiopulmonary exercise test (CPET). Those categorized as having a moderate-to-high risk of cardiac arrest during exercise are advised to engage in center-based CR (CBCR). However, participation rates in CBCR remain suboptimal, with approximately 30% of eligible patients participating worldwide. This low participation rate can be attributed to challenges, such as limited center accessibility, geographical distance, financial constraints, and time constraints [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In South Korea, the implementation rate of CBCR stands at only 28%, lower than the global average (12% in secondary medical centers and 41% in tertiary centers), primarily due to a shortage of staff and space [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Moreover, following the World Health Organization\u0026rsquo;s declaration of the pandemic caused by the new coronavirus, SARS-CoV-2, the participation rate in CBCR further decreased [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHome-based CR (HBCR) has been introduced as an alternative to CBCR to improve participation. According to a 2019 Cochrane review, both HBCR and CBCR demonstrated comparable effects on clinical outcomes and quality of life among individuals with heart failure and acute coronary syndrome [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. With the improvement of telemedicine, HBCR using remote monitoring devices are increasingly prevalent. By monitoring patients\u0026rsquo; objective data, such as HR, ECG, and physical activity, individuals can safely engage in exercise programs, leading to a reduction in anxiety [\u003cspan additionalcitationids=\"CR13 CR14 CR15 CR16\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eStudies have found that an early initiation of CR following cardiac surgery not only reduces mortality and shortens hospital stays but also, importantly, does not lead to an increase in adverse events [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. However, to our knowledge, majority of previous studies on HBCR with remote monitoring have been conducted at least 1 month after surgery or discharge. Consequently, studies exploring the safety and effectiveness of home-based telerehabilitation within the first month following open-heart surgery are lacking.\u003c/p\u003e \u003cp\u003eTherefore, we aimed to evaluate the safety and feasibility of an early CR program using remote ECG monitoring during an early postoperative period in patients who underwent cardiac surgery.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy population\u003c/h2\u003e \u003cp\u003eThis was a single-center prospective study that included patients who underwent open-heart surgery at the OO Hospital. The Institutional Review Board of OO Hospital approved the study design (approval no: 2021AN0089). Between November 2021 and April 2023, patients who underwent open-heart surgery and were referred to the Rehabilitation Medicine Department for inpatient CR were screened for eligibility.\u003c/p\u003e \u003cp\u003ePatients were included in the study if they were aged\u0026thinsp;\u0026gt;\u0026thinsp;18 years, had a left ventricular ejection fraction\u0026thinsp;\u0026gt;\u0026thinsp;35.0%, were capable of performing an exercise test, were able to comprehend instructions related to a mobile application and ECG monitoring patch used during the trial, and were able to ambulate independently. Informed consent was obtained from all the participants before enrollment. Exclusion criteria encompassed individuals with a history of cardiac arrest or those with an implantable cardioverter-defibrillator, unstable vital signs, cognitive impairment preventing understanding of the exercise protocol and instructions, lower extremity musculoskeletal or neurological diseases complicating exercise training, or those unable to ambulate independently.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eStudy protocol\u003c/h2\u003e \u003cp\u003eOn average, 5 d postoperatively, the participants initiated a low-intensity inpatient CR program while wearing an ECG monitoring device. Before starting the program, baseline data, including grip strength (GS), 6-min walk distance (6 MWD), EuroQol-5 dimension (EQ-5D), short-form 36-item health survey (SF-36), and Korean Activity Scale/Index (KASI), were collected. Outcomes were measured at three time points: starting CR (average 5 d postoperatively) (T1), before discharge from the hospital (approximately 9 d postoperatively) (T2), and at the end of the study period (approximately 3\u0026ndash;4 weeks postoperatively) (T3). The exercise stress test and squat endurance test were conducted at two points: T2 and T3 (Fig.\u0026nbsp;1).\u003c/p\u003e \u003cp\u003eBefore starting the exercise program, the patients were instructed on proper utilization of the ECG patch monitor and mobile applications. They were advised to wear the patches consistently throughout the study period. The inpatient CR program was conducted five times a week for a total of 1 h. The program consisted of a 10-min warm-up exercise, 10-min of resistance training, 30 min of aerobic exercise, and a 10-min cool-down phase. If the patient experienced dyspnea during the exercise, a brief rest period was encouraged before resuming the program.\u003c/p\u003e \u003cp\u003eBefore discharge, approximately 9 d postoperatively, the patients underwent a symptom-limited submaximal exercise test using an ergometer and squat endurance test. These assessments were aimed at determining the appropriate intensity and target HR for subsequent home-based aerobic and strength exercises.\u003c/p\u003e \u003cp\u003eFor the incremental symptom-limited exercise test, subjects lay on a cycle ergometer (Corival Recumbent cpet 969900, Lode, Groningen, Netherlands) (Fig.\u0026nbsp;2) and pedaled the bicycle with an initial load of 0 watts and pedaling frequency of 60 rpm, and the workload was increased by 20 watts every 2 min. The test was terminated if any absolute indications for discontinuation during the examination were observed or if pre-established termination criteria were met (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). During the test, HR, peak oxygen consumption, peak metabolic equivalent of task (MET), maximal work capacity (Wmax), peak respiratory exchange ratio, peak rate of perceived exertion (RPE), peak dyspnea scale, peak angina scale, and total exercise duration were measured. Metabolic equivalent of task was automatically calculated, with one MET defined as the oxygen consumption level during seated rest (equivalent to 3.5 mL of oxygen per kg per min) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The Wmax was determined by the highest intensity that an individual can sustain for 30 s, beyond which it becomes unsustainable. Following 2 weeks of home-based exercise, the patients revisited the hospital for a follow-up exercise test. The test was conducted on a treadmill instead of a cycle ergometer.\u003c/p\u003e \u003cp\u003eA squat endurance test [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] was conducted to assess the intensity of the targeted resistance exercise. The participants leaned against the wall, stood with their feet shoulder-width apart, and initiated squats by flexing their knees at a 90\u003cb\u003e\u0026deg;\u003c/b\u003e angle from a standing position. The test was performed with the intensity set between 40\u0026ndash; 60% of the HR reserve, determined through symptom-limited submaximal exercise testing, and continued until it reached a slightly challenging level (RPE 13).\u003c/p\u003e \u003cp\u003eAfter discharge, the patients underwent a 2-week HBCR program. For aerobic exercises, the patients were informed of their target HR using the Karvonen formula [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], with an exercise intensity set at 40\u0026ndash;55% of the HR reserve determined from an incremental submaximal exercise test. The target HR can be estimated as follows: (target HR = resting HR + [0.40\u0026thinsp;\u0026minus;\u0026thinsp;0.55] \u0026times; [peak HR\u0026thinsp;\u0026minus;\u0026thinsp;resting HR]). Since all the patients maintained their HRs within the target range (40\u0026ndash;60% of peak HR) when reaching RPE 13, we recommended that they perform the same number of squat repetitions for their home exercise.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eRemote ECG monitoring system\u003c/h2\u003e \u003cp\u003eTo monitor remote ECG data, we used MEMO Patch (MEMO Patch, HUINNO Co., Ltd., Seoul, South Korea) (Fig.\u0026nbsp;3), the first ambulatory ECG device approved by the Korean Food and Drug Administration. This adhesive single-lead patch can store ECG data for up to 14 d. A cohort study in Korea showed that using the patch for 7-d continuous ECG monitoring was more effective in detecting supraventricular tachycardia than the traditional 24-h Holter monitor [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The recorded ECG data from the patch was subjected to analysis using MEMO Artificial intelligence (AI), which was constructed and trained by HUINNO for arrhythmia classification [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The AI algorithm employed in this study integrates multiple components tailored for specific tasks within cardiac signal analysis. First, it uses a convolutional neural network architecture with skip connections engineered specifically to detect episodic arrhythmias and filter out noise signals, enhancing the reliability of detection. Second, a dedicated segmentation and classification network was implemented, which was finely tuned to identify and delineate the P, QRS, and T segments of the ECG, enabling detailed feature extraction from these critical signal components. Finally, a sophisticated postprocessing algorithm synthesizes the information from the previous stages to refine the overall analysis. This multifaceted approach ensures a robust and precise initial analysis by leveraging deep learning techniques to improve diagnostic accuracy.\u003c/p\u003e \u003cp\u003eAfter the ECG data were analyzed using AI, the technicians manually reviewed and verified the AI-generated diagnosis. If necessary, the diagnosis was revised after confirmation by cardiologists.\u003c/p\u003e \u003cp\u003eThe patients were instructed to wear the patch consistently throughout the study period. In addition, they were provided with mobile phones featuring internet connectivity, and the device was preloaded with an application connected to the ECG patch. During the daily exercise, the patients activated the application to transmit their ECG data, and upon completion, they deactivated the application. Subsequently, the ECG data were transmitted in real-time to the HUINNO Cloud. Medical doctors closely monitored the data using the MEMO Care website and provided feedback to the patients through telephone calls (Fig.\u0026nbsp;4). If ventricular fibrillation, sustained ventricular tachycardia, or ST segment elevation\u0026thinsp;\u0026gt;\u0026thinsp;1 mm was observed in the ECG data, the researchers planned to recommend discontinuing home-based exercises and scheduling an earlier hospital visit via telephone calls. Additionally, the patients were instructed to report \u0026ldquo;patients triggered events\u0026rdquo; by pressing the button on the patch if they experienced angina chest pain, dizziness, or syncope.\u003c/p\u003e \u003cp\u003eAt the end of each week, the participants visited the hospital to return the patch, where doctors offered further guidance by reviewing the weekly reports available on the website. The weekly report covers the entire monitoring period and includes data on minimum, average, and maximum HRs, as well as details on the number and duration of various arrhythmia events, such as atrial fibrillation (AF), supraventricular tachycardia, ventricular fibrillation, atrial premature complexes, ventricular premature complexes, and patient-triggered events (Fig.\u0026nbsp;5). After the study period, the participants completed a 14-item self-report questionnaire on their satisfaction with the ECG patch.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003ePhysical assessments\u003c/h2\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003eGS\u003c/h2\u003e \u003cp\u003eThe GS test is a widely employed method for assessing muscle strength and serves as a predictor of various health outcomes, including cardiovascular mortality, length of hospital stay, functional status, and perioperative complications [\u003cspan additionalcitationids=\"CR26\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. To assess GS, the participants were instructed to apply maximal force alternately with their left and right hands on a handheld dynamometer (JAMAR PLUS\u0026thinsp;+\u0026thinsp;Digital Hand Dynamometer; Sammons Preston Rolyan, Bolingbrook, IL, USA ) and repeat this process twice. Following two attempts, maximal grip power (kg) was recorded. The greater GS between the two hands was used for further analysis.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e6 MWD\u003c/h2\u003e \u003cp\u003eThe 6 MWD is a simple and safe test that has been found to significantly reflect functional status and activities of daily living [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The participants were instructed to walk along a 30-m corridor for 6 min, aiming to cover as much distance as possible while maintaining a perceived intensity between three (moderate) and four (somewhat strong) on the Borg CR scale (CR 10) [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Rest was permitted if participants felt exhausted, and the test was halted if they experienced dyspnea or chest pain that impeded daily activities. Elapsed time was recorded for the patients at each minute of assessment without additional feedback or encouragement. Oxygen saturation, blood pressure, and HR were measured before and after the test, and the distance covered during the 6-min period was recorded.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eSelf-reported survey\u003c/h2\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003eSF-36\u003c/h2\u003e \u003cp\u003eThe SF-36 is a widely used self-reported quality-of-life questionnaire consisting of 36 items. It assesses physical health using physical function, physical role, bodily pain, and general health. Additionally, it evaluates mental health using vitality, social function, role emotional, and mental health. These eight subscales were further divided into 35 items, with the remaining one addressing health change perception, for a total of 36 detailed items. Assigning scores to the detailed items within each of the eight subscales and adding them yields a total score ranging from 0 (indicating the poorest health) to 100 (indicating the best health). The scores can be summarized into two main areas: the physical component summary (PCS) and mental component summary (MCS). In the general population, scores for each component are expected to have a mean of 50 and standard deviation of 10 [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. We used the Korean version of the questionnaires to ensure that patients can easily comprehend and complete the test [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eKASI\u003c/h2\u003e \u003cp\u003eThe Korean Activity Scale/Index (KASI) [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e] is a Korean-translated version of the Duke Activity Status Index, which is a 12-item scale survey designed to assess functional capacity and quality of life. This test demonstrated a significant correlation between peak oxygen uptake [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] and the occurrence of major adverse cardiac events [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. The participants were asked to self-assess the questionnaires, and the total scores were determined based on their responses.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eEQ-5D\u003c/h2\u003e \u003cp\u003eThe EQ-5D was used to assess health-related quality of life in our study [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. It consists of five dimensions of questions about current health state (mobility, self-care, and usual activities), which comprises five dimensions concerning current health status (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), with each dimension consisting of a three-point scale (no problem, moderate problem, and severe problems). Responses to each question were transformed into final scores using Korean value set calculations, ranging between \u0026minus;\u0026thinsp;0.171 and 1. A score of 1 indicates a \u0026ldquo;healthy state without problems,\u0026rdquo; while a score of 0 represents \u0026ldquo;death,\u0026rdquo; and scores below 0 indicate a state \u0026ldquo;worse than death.\u0026rdquo; [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analyses were performed using IBM SPSS Statistics for Windows version 26. To compare baseline characteristics between CABG and non-CABG groups, the Student\u0026rsquo;s t-test was used for continuous variables, while the chi-square test was used for categorical variables. A mixed linear model with an unstructured covariance matrix was used to analyze changes in repeatedly measured primary and secondary outcomes over time. The model incorporated covariates, such as time, group, 6 MWD, EQ-5D, SF-36, KASI, squat endurance test, and measurements obtained using submaximal exercise tests. Statistical significance was considered at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eBaseline characteristics\u003c/h2\u003e \u003cp\u003eBaseline demographics and disease-related characteristics of the participants are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Of the 22 patients enrolled in the study, six dropped out during the follow-up period. Three patients withdrew from the study due to an inability to maintain continuous observation, as they did not routinely wear the monitoring device or adhere to the study protocol. Two patients were excluded because they were diagnosed with COVID-19. One patient discontinued participation due to poor general health. Sixteen patients, with an average age (standard deviation) of 63.38 (1.89) years, successfully completed the study, and twelve (75.0%) of them were males. Median (interquartile range [IQR] ) time to the initiation of CR was 5 (5\u0026ndash;6) d. Among the participants, seven (43.8%) underwent CABG, seven (43.8%) underwent valve replacement surgery, one underwent total arch replacement surgery (6.3%), and one received coronary artery fistulectomy (6.3%).\u003c/p\u003e \u003cp\u003eComparison between patients who underwent CABG and those who underwent non-CABG surgery showed no significant differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eChanges over time in participants outcomes\u003c/h2\u003e \u003cp\u003eComparison between the second assessment at T2 and final assessment at T3 (T2-T3) showed that peak VO\u003csub\u003e2\u003c/sub\u003e increased from 12.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57 mL/kg/min to 17.93\u0026thinsp;\u0026plusmn;\u0026thinsp;1.25 mL/kg/min (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01), peak MET improved from 3.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28 mL/kg/min to 5.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28 mL/kg/min (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01), and peak HR increased from 110.19\u0026thinsp;\u0026plusmn;\u0026thinsp;5.53 to 122.12\u0026thinsp;\u0026plusmn;\u0026thinsp;5.53 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Additionally, the squat endurance test demonstrated improvement from 16.69\u0026thinsp;\u0026plusmn;\u0026thinsp;2.31 to 21.81\u0026thinsp;\u0026plusmn;\u0026thinsp;2.31 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01).\u003c/p\u003e \u003cp\u003eCompared to the initial assessment at T1, the GS showed improvement from 28.30\u0026thinsp;\u0026plusmn;\u0026thinsp;1.66 kg to 30.40\u0026thinsp;\u0026plusmn;\u0026thinsp;1.70 kg at T3 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.02). However, no significant change was noted between T2 (30.62\u0026thinsp;\u0026plusmn;\u0026thinsp;1.68 kg) and T3. The 6 MWD increased from 249.33\u0026thinsp;\u0026plusmn;\u0026thinsp;20.92 m at T1 to 387.02\u0026thinsp;\u0026plusmn;\u0026thinsp;22.77 m at T3 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). The EQ-5D scores improved from 0.59\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03 at T1 to 0.82\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03 at T3. The KASI improved from 5.44\u0026thinsp;\u0026plusmn;\u0026thinsp;0.58 at T1 to 26.11\u0026thinsp;\u0026plusmn;\u0026thinsp;2.70 at T3 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Total scores of the SF-36 showed improvement from 83.99\u0026thinsp;\u0026plusmn;\u0026thinsp;3.40 at T1 to 122.82\u0026thinsp;\u0026plusmn;\u0026thinsp;6.06 at T3 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). The PCS of SF-36 significantly improved from 32.16\u0026thinsp;\u0026plusmn;\u0026thinsp;1.55 at T1 to 57.69\u0026thinsp;\u0026plusmn;\u0026thinsp;3.20 at T3 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Although the MCS score showed a significant increase (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002) between T1 (51.83\u0026thinsp;\u0026plusmn;\u0026thinsp;2.59) and T3 (64.15\u0026thinsp;\u0026plusmn;\u0026thinsp;3.02), no significant difference was noted between T2 and T3 (p\u0026thinsp;=\u0026thinsp;0.09) (Fig.\u0026nbsp;6).\u003c/p\u003e \u003cp\u003eIn the subgroup analysis, the CABG group demonstrated a greater increase in 6 MWD (102.29 m, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01) than the non-CABG group. However, no significant differences were observed in other measurements between the two groups.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eECG recording results\u003c/h2\u003e \u003cp\u003eBetween time points T1 and T3, the average duration of ECG monitoring increased from 125 hours to 179 hours. The median occurrence of atrial premature complex changed from 261 to 155, while that of ventricular premature complex decreased from 135 to 88.5. Atrial fibrillation was reported in five patients, and nonsustained ventricular tachycardia events were reported in six patients.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eAdverse effects\u003c/h2\u003e \u003cp\u003eRegarding safety concerns, there were no reported serious adverse events, such as hospitalization, cardiac arrest, or death. Throughout the study period, no instances of sustained ventricular tachycardia or fibrillation were recorded using an ECG monitoring device.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003ePatient satisfaction regarding the remote monitoring-based HBCR program\u003c/h2\u003e \u003cp\u003eBased on the final self-report questionnaires, 12 (75.0%) patients completed the HBCR program with satisfactory remote ECG monitoring. Participants primarily expressed satisfaction because they felt reassured by the real-time HR monitoring through the mobile application (75.0%) and because they were able to review the automatically saved ECG records later (68.8%). Additionally, they appreciated their ability to regulate exercise intensity with alarms set above individual HR thresholds. In terms of areas that needed improvement, four (25.0%) patients reported experiencing a skin rash and itching sensation at the patch attachment site. Three (18.8%) patients mentioned that the patch detached easily when sweating occurred after the exercise. Two (12.5%) patients reported Bluetooth disconnection. Additionally, three (18.8%) patients, with an average age of 73.3 years, encountered difficulties in manipulating the mobile application due to their advanced age.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe principal finding of this study was that initiating early CR within 1 month after the first-time open-heart surgery, using an ECG monitoring device, resulted in significant improvements in exercise capacity, quality of life, and various functional outcomes.\u003c/p\u003e \u003cp\u003eTo the best of our knowledge, the present study is the first to validate the safety and effectiveness of initiating early rehabilitation using a remote ECG device coupled with real-time feedback among patients undergoing different cardiac surgeries, such as CABG, valve operations, and aortic surgeries. Previous studies using ECG monitoring systems for remote postopen-heart surgery monitoring primarily began exercise programs during the phase II period [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e], with a lack of studies initiating home exercise programs within 2 weeks postoperatively [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Even though all patients who undergo open-heart surgery are recommended to receive CR, the CR participation rate remains suboptimal [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Home-based exercise training with a telemonitoring system could serve as an effective alternative model to achieve this objective. Previous studies have indicated that telerehabilitation with various monitoring systems has a comparable effect to hospital-based rehabilitation [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan additionalcitationids=\"CR42\" citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. Recent CR guidelines advocate for ECG-monitored exercise during an early postonset period [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. An ECG monitoring system, capable of recording one-lead cardiac rhythm, detecting arrhythmias, and monitoring HR, can enhance adherence to CR. In our study, we observed a notable increase in the total duration of patients wearing the ECG-monitoring device over a span of approximately 3 weeks. Additionally, receiving real-time feedback from the medical team instills confidence and a sense of safety among patients, thereby further improving their participation rate.\u003c/p\u003e \u003cp\u003eAlthough our study only included an intervention group without a control group that did not participate in the exercise program, our results showed improvements in various exercise parameters (peak VO\u003csub\u003e2\u003c/sub\u003e, MET, and peak HR) during incremental exercise tests after 2 weeks of home-based exercise programs. These findings support previous reports highlighting that telerehabilitation offers benefits comparable to standard rehabilitation therapy [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan additionalcitationids=\"CR46\" citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. Additionally, the total KASI and EQ-5D scores, which indicate the patient\u0026rsquo;s activity levels and quality of life, showed a significant increase compared to the initial assessment and discharge. As KASI scores are known to correlate with oxygen capacity [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], it suggests that the program plays a role in enhancing cardiovascular function. Similarly, the total SF-36 score significantly increased after 2 weeks of CR. The PCS measures of the SF-36 demonstrated significant improvement in the final test compared with the initial assessment and discharge status. However, only the MCS measures of SF-36 showed a significant change between the final and initial measurements. No significant differences were observed between the final follow-up and discharge statuses. These improvements signify that despite the burden of open-heart surgery, the participants demonstrated significant enhancements in physical function and overall quality of life after completing the 2-week exercise program.\u003c/p\u003e \u003cp\u003eFrom a safety perspective, conducting HBCR with remote monitoring shortly after open-heart surgery, within 2-weeks postoperation, did not increase the risk of postoperative adverse events. Atrial fibrillation is the most common complication after cardiac surgery, occurring in 15.0\u0026ndash;40.0% of cases after CABG and 37.0\u0026ndash;50.0% after valve surgery [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. Nonsustained ventricular arrhythmias are reported in up to 36.0% of cases [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e], whereas sustained ventricular arrhythmias occur in 0.4\u0026ndash;1.4% of cases after cardiac surgery [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. In our study, AF was detected in five (31.3%) patients, while nonsustained ventricular tachycardia was observed in six (37.5%). Among them, four patients experienced AF for the first time postoperatively during a remote ECG-monitoring exercise training session. However, the duration of AF in these cases was brief, ranging between 6\u0026ndash;10 min. Throughout the training session, none of the participants experienced life-threatening events, such as sustained ventricular tachycardia or ventricular fibrillation. Furthermore, no instances of patients being readmitted to the hospital or emergency department were noted during the program. Ennis et al. observed that commencing exercise training as early as 2 weeks after sternotomy enhances functional outcomes and the 6 MWD sooner [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e]. This early intervention allows patients to regain social function and economic productivity earlier, contributing to an improved quality of life without any substantial additional risks. Consequently, the patients were able to achieve aerobic exercise capacity sooner, potentially leading to earlier improvements in functional activity. However, in Korea, exercise therapy is still postponed for 4 weeks owing to general condition and suture site concerns following cardiac surgery [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. Our findings suggest that initiating remote ECG-monitoring-based HBCR within 2 weeks postoperatively can be safely implemented in patients who have recently undergone cardiac surgery.\u003c/p\u003e \u003cp\u003eThrough feedback gathered from patient surveys, we identified key areas for enhancing the effectiveness of remote CR. A smartphone application integrated with an ECG monitoring system has great potential for HBCR programs [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e]. However, to encourage broader usage, ensuring that patients can easily use both the application and device is crucial. In our study, 18.8% of the participants reported difficulties with the mobile application. Given that many cardiac surgery patients are older and less familiar with mobile technology, simplifying procedures, such as device application and removal, as well as app navigation, is essential. Additionally, 12.5% of patients faced challenges with Bluetooth connectivity, emphasizing the need to improve internet stability for broader and safer adoption of telerehabilitation. Moreover, addressing skin issues is crucial as participants cannot readily access advice or patch-exchange services while engaging in home-based exercises. Therefore, improving patches is essential for alleviating attachment problems and skin irritation.\u003c/p\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eLimitation\u003c/h2\u003e \u003cp\u003eThis study has several important limitations. First, the absence of a control group that did not receive exercise training made it challenging to accurately gauge the true effect of CR on functional outcomes and aerobic capacity. Second, majority of the participants were males aged 50\u0026ndash;70 years, and because of the small sample size, generalizing the study findings is difficult. Third, the initial submaximal exercise test used a cycle ergometer to minimize the burden on patients, whereas the follow-up test employed a treadmill. This discrepancy may have introduced heterogeneity into the final measurements. Fourth, since the final measurements were conducted about 3\u0026ndash;4 weeks postoperatively, there were no long-term follow-up results regarding functional outcomes or aerobic capacity. In the future, a large-scale randomized controlled trial with long-term follow-up is warranted to validate the findings of our study.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe findings of this study suggest that starting HBCR exercise training within 1 month after cardiac surgery, combined with remote ECG monitoring, leads to beneficial outcomes for aerobic capacity, functional status, and quality of life. No significant adverse events were reported during the study period. These results provide valuable insights for clinicians, enabling them to confidently design HBCR with ECG monitoring within the first month after an open heart surgery. Further studies on CR programs using various wearable devices capable of tracking diverse physical activities of patients, including ECG monitoring, is necessary for continued advancement.\u003c/p\u003e "},{"header":"Abbreviations","content":"\u003cp\u003eCABG\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;coronary artery bypass grafting\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCR\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;cardiac rehabilitation\u003c/p\u003e\n\u003cp\u003eHR\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;heart rate\u003c/p\u003e\n\u003cp\u003eECG\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;electrocardiogram\u003c/p\u003e\n\u003cp\u003eCPET\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;cardiopulmonary exercise test\u003c/p\u003e\n\u003cp\u003eCBCR\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;center-based cardiac rehabilitation\u003c/p\u003e\n\u003cp\u003eHBCR\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;home-based cardiac rehabilitation\u003c/p\u003e\n\u003cp\u003eGS\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;grip strength\u003c/p\u003e\n\u003cp\u003e6MWD\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;6-min walk distance\u003c/p\u003e\n\u003cp\u003eEQ-5D\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;EuroQol-5 dimension\u003c/p\u003e\n\u003cp\u003eSF-36\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;short-form 36-item health survey\u003c/p\u003e\n\u003cp\u003ePCS\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Physical component summary\u003c/p\u003e\n\u003cp\u003eMCS\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Mental component summary\u003c/p\u003e\n\u003cp\u003eKASI\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Korean Activity Scale/Index\u003c/p\u003e\n\u003cp\u003eMET\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;metabolic equivalent of task\u003c/p\u003e\n\u003cp\u003eWmax\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;maximal work capacity\u003c/p\u003e\n\u003cp\u003eRPE \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; rate of perceived exertion\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStudy procedures were approved by the\u0026nbsp;the Institutional Review Board of Korea University Anam Hospital (approval no: 2021AN0089).\u0026nbsp;Written informed consent was\u0026nbsp;obtained from patients. For illiterate patients, informed consent was obtained\u0026nbsp;from the patient\u0026rsquo;s legal guardian.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe obtained written informed consent for the publication of the individual\u0026rsquo;s data and image included in the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors received no financial support for the research, authorship, and/or publication of this article\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study design and approval of the final version of the table.\u0026nbsp;\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eYeon Mi Kim, M.D.:\u0026nbsp;\u003c/strong\u003eWriting - Original Draft, Formal Analysis, Investigation, Validation, Resources.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eBo Ryun Kim, M.D., Ph.D.:\u0026nbsp;\u003c/strong\u003eConceptualization, Methodology, Formal Analysis, Investigation, Writing - Review \u0026amp; Editing, Funding Acquisition\u003cstrong\u003e.\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eSung Bom Pyun, M.D., Ph.D.:\u0026nbsp;\u003c/strong\u003eProject Administration, Writing - Review \u0026amp; Editing, Supervision.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eJae Seung Jung, M.D., Ph.D.:\u0026nbsp;\u003c/strong\u003eInvestigation, Resources, Writing - Review \u0026amp; Editing,\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eHee Jung Kim, M.D., Ph.D.:\u0026nbsp;\u003c/strong\u003eResources, Validation, Writing - Review \u0026amp; Editing,\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eHo Sung Son, M.D., Ph.D.:\u0026nbsp;\u003c/strong\u003eProject Administration, Resources, Writing - Review \u0026amp; Editing, Supervision.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was supported by a Korea University Grant.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and analyzed during this study are available from the\u003c/p\u003e\n\u003cp\u003ecorresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eStatistics Korea.Deaths and death rates by cause(104 item)/By sex/By age(five-year age). 2022. https://kosis.kr/statHtml/statHtml.do?orgId=101\u0026amp;tblId=DT_1B34E01\u0026amp;conn_path=I2\u0026amp;language=en. 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J Am Coll Cardiol. 2006;47:S36-S43. https://doi.org/10.1016/j.jacc.2005.03.080.\u003c/li\u003e\n\u003cli\u003eRabin R, de Charro F. EQ-5D: a measure of health status from the EuroQol Group. Ann Med. 2001;33:337-43. https://doi.org/10.3109/07853890109002087.\u003c/li\u003e\n\u003cli\u003eKim MH, Cho YS, Uhm WS, Kim S, Bae SC. Cross-cultural adaptation and validation of the Korean version of the EQ-5D in patients with rheumatic diseases. Qual Life Res. 2005;14:1401-6. https://doi.org/10.1007/s11136-004-5681-z.\u003c/li\u003e\n\u003cli\u003eNam HS. EQ‐5D Korean valuation study using time trade of method. Seoul: Korea Centers for Disease Control and Prevention. 2007.\u003c/li\u003e\n\u003cli\u003eWolszakiewicz J, Piotrowicz E, Foss-Nieradko B, Dobraszkiewicz-Wasilewska B, Piotrowicz R. A novel model of exercise walking training in patients after coronary artery bypass grafting. Kardiol Pol. 2015;73:118-26. https://doi.org/10.5603/KP.a2014.0165.\u003c/li\u003e\n\u003cli\u003eVongvanich P, Bairey Merz CN. Supervised exercise and electrocardiographic monitoring during cardiac rehabilitation. Impact on patient care. J Cardiopulm Rehabil. 1996;16:233-8. https://doi.org/10.1097/00008483-199607000-00004.\u003c/li\u003e\n\u003cli\u003eScalvini S, Zanelli E, Comini L, Tomba MD, Troise G, Giordano A. Home-based exercise rehabilitation with telemedicine following cardiac surgery. J Telemed Telecare. 2009;15:297-301. https://doi.org/10.1258/jtt.2009.090208.\u003c/li\u003e\n\u003cli\u003eAdes PA, Pashkow FJ, Fletcher G, Pina IL, Zohman LR, Nestor JR. A controlled trial of cardiac rehabilitation in the home setting using electrocardiographic and voice transtelephonic monitoring. Am Heart J. 2000;139:543-8. https://doi.org/10.1016/s0002-8703(00)90100-5.\u003c/li\u003e\n\u003cli\u003ePiotrowicz E, Baranowski R, Bilinska M, Stepnowska M, Piotrowska M, W\u0026oacute;jcik A, et al. A new model of home-based telemonitored cardiac rehabilitation in patients with heart failure: effectiveness, quality of life, and adherence. Eur J Heart Fail. 2010;12:164-71. https://doi.org/10.1093/eurjhf/hfp181.\u003c/li\u003e\n\u003cli\u003eLee Y, Lee J, Seo H, Kim K, Min D, Lee J, et al. Effects of Home-based Exercise Training with Wireless Monitoring on the Left Ventricular Function of Acute Coronary Syndrome Patients. J Phys Ther Sci. 2013;25:631-3. https://doi.org/10.1589/jpts.25.631.\u003c/li\u003e\n\u003cli\u003eWenger NK. Current status of cardiac rehabilitation. J Am Coll Cardiol. 2008;51:1619-31. https://doi.org/10.1016/j.jacc.2008.01.030.\u003c/li\u003e\n\u003cli\u003eMilewski K, Balsam P, Kachel M, Sitek B, Kolarczyk-Haczyk A, Skoczyński S, et al. Actual status and future directions of cardiac telerehabilitation. Cardiol J. 2023;30:12-23. https://doi.org/10.5603/CJ.a2022.0104.\u003c/li\u003e\n\u003cli\u003eHuang K, Liu W, He D, Huang B, Xiao D, Peng Y, et al. Telehealth interventions versus center-based cardiac rehabilitation of coronary artery disease: A systematic review and meta-analysis. Eur J Prev Cardiol. 2015;22:959-71. https://doi.org/10.1177/2047487314561168.\u003c/li\u003e\n\u003cli\u003eHwang R, Bruning J, Morris N, Mandrusiak A, Russell T. A Systematic Review of the Effects of Telerehabilitation in Patients With Cardiopulmonary Diseases. J Cardiopulm Rehabil Prev. 2015;35:380-9. https://doi.org/10.1097/hcr.0000000000000121.\u003c/li\u003e\n\u003cli\u003eBoons J, Van Biesen S, Fivez T, de Velde MV, Al Tmimi L. Mechanisms, Prevention, and Treatment of Atrial Fibrillation After Cardiac Surgery: A Narrative Review. J Cardiothorac Vasc Anesth. 2021;35:3394-403. https://doi.org/10.1053/j.jvca.2020.11.030.\u003c/li\u003e\n\u003cli\u003eYeung-Lai-Wah JA, Qi A, McNeill E, Abel JG, Tung S, Humphries KH, et al. New-onset sustained ventricular tachycardia and fibrillation early after cardiac operations. Ann Thorac Surg. 2004;77:2083-8. https://doi.org/10.1016/j.athoracsur.2003.12.020.\u003c/li\u003e\n\u003cli\u003eChung MK. Cardiac surgery: postoperative arrhythmias. Crit Care Med. 2000;28:N136-N44. https://doi.org/10.1097/00003246-200010001-00005.\u003c/li\u003e\n\u003cli\u003eEnnis S, Lobley G, Worrall S, Evans B, Kimani PK, Khan A, et al. Effectiveness and Safety of Early Initiation of Poststernotomy Cardiac Rehabilitation Exercise Training: The SCAR Randomized Clinical Trial. JAMA Cardiol. 2022;7:817-24. https://doi.org/10.1001/jamacardio.2022.1651.\u003c/li\u003e\n\u003cli\u003eMaines TY, Lavie CJ, Milani RV, Cassidy MM, Gilliland YE, Murgo JP. Effects of cardiac rehabilitation and exercise programs on exercise capacity, coronary risk factors, behavior, and quality of life in patients with coronary artery disease. South Med J. 1997;90:43-9. https://doi.org/10.1097/00007611-199701000-00010.\u003c/li\u003e\n\u003cli\u003eKim C, Sung J, Han JY, Jee S, Lee JW, Lee JH, et al. Current Status of Cardiac Rehabilitation in the Regional Cardiocerebrovascular Centers in Korea. J Clin Med. 2021;10:5079. https://doi.org/10.3390/jcm10215079.\u003c/li\u003e\n\u003cli\u003eWorringham C, Rojek A, Stewart I. Development and feasibility of a smartphone, ECG and GPS based system for remotely monitoring exercise in cardiac rehabilitation. PLoS One. 2011;6:e14669. https://doi.org/10.1371/journal.pone.0014669.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Termination criteria for\u0026nbsp;the\u0026nbsp;symptom-limited submaximal exercise tests\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003eAbsolute indication for stop test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003ePre-established termination criteria\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003e- ST-segment elevation \u0026gt;1 mm without abnormal Q waves in the ECG channels, excluding V1 and aVR\u003c/p\u003e\n \u003cp\u003e- Decrease in SBP \u0026gt;10 mmHg or a drop below resting SBP\u003c/p\u003e\n \u003cp\u003e- Severe or higher-grade angina (Angina scale Grade 3\u0026ndash;4)\u003c/p\u003e\n \u003cp\u003e- Able to ambulate without physical assistance\u003c/p\u003e\n \u003cp\u003e- Exacerbation of neurological symptoms (e.g., dizziness and ataxia)\u003c/p\u003e\n \u003cp\u003e- Cyanosis or pallor\u003c/p\u003e\n \u003cp\u003e- Persistent ventricular tachycardia\u003c/p\u003e\n \u003cp\u003e- Patient\u0026apos;s desire to discontinue the test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" valign=\"top\"\u003e\n \u003cp\u003e- HR \u0026gt;120 beats per minute.\u003c/p\u003e\n \u003cp\u003e- Reaching 70% of the maximum predicted heart rate based on the patient\u0026rsquo;s age.\u003c/p\u003e\n \u003cp\u003e- Achieving a predetermined MET level (typically 5\u0026ndash;7).\u003c/p\u003e\n \u003cp\u003e- Uncontrolled medical condition\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e- RPE (rate of perceived exertion) exceeds 15 on the Borg 6\u0026ndash;20 grade scale.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eSBP, systolic blood pressure; HR, heart rate; MET, metabolic equivalent of task\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e. Baseline clinical characteristics and initial 6\u0026nbsp;MWD, EQ5D, KASI, and SF36\u0026nbsp;results (N=16)\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"677\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.72189349112426%\" rowspan=\"2\"\u003e\n \u003cp\u003eVariables\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.715976331360945%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.562130177514796%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003eSubgroup analysis\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"28.84160756501182%\" colspan=\"2\"\u003e\n \u003cp\u003eTotal (N=16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.84160756501182%\" valign=\"top\"\u003e\n \u003cp\u003eCABG (N=7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.84160756501182%\" valign=\"top\"\u003e\n \u003cp\u003eNon-CABG (N=9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.47517730496454%\" valign=\"top\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\"\u003e\n \u003cp\u003e63.38 \u0026plusmn; 1.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\"\u003e\n \u003cp\u003e64.43 \u0026plusmn; 7.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\"\u003e\n \u003cp\u003e62.56 \u0026plusmn; 8.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.639\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eSex, males/females\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\"\u003e\n \u003cp\u003e12 (75)/4 (25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\"\u003e\n \u003cp\u003e12 (86)/1 (14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\"\u003e\n \u003cp\u003e6 (67)/3 (33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.536\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eHeight (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e164.63 \u0026plusmn; 2.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e164.33 \u0026plusmn; 8.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e166.63 \u0026plusmn; 9.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.618\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eWeight (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e66.23 \u0026plusmn; 2.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e67.71 \u0026plusmn; 6.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e65.08 \u0026plusmn; 11.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.604\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eBody mass index (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e24.05 \u0026plusmn; 0.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e25.04 \u0026plusmn; 1.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e23.28 \u0026plusmn; 2.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.096\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eTime to start cardiac rehabilitation (days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e5.00 (5.00; 6.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e5.00 (4.00; 6.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e6.00 (5.00; 6.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.174\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eGrip strength test (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e28.19 \u0026plusmn; 1.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e28.24 \u0026plusmn; 6.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e28.04 \u0026plusmn; 8.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.959\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003e6 minute walk distance (m)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e262.00 \u0026plusmn; 21.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e237.57 \u0026plusmn; 43.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e281.00 \u0026plusmn; 104.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.283\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eKorean Activity Scale/Index (KASI)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e4.90 (3.70;7.08)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e4.90 (3.70;4.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e6.70 (3.70;9.70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.174\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eEuroQol-5 dimension (EQ5D)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e0.68 (0.51;0.68)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e0.68 (0.47;0.68)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e0.68 (0.51;0.70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.758\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003eShort-form 36-item health survey (SF36)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Total score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e86.79 \u0026plusmn; 4.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e84.82 \u0026plusmn; 9.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e88.33 \u0026plusmn; 21.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.689\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Physical component summary (PCS)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e33.61 \u0026plusmn; 1.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e34.20 \u0026plusmn; 3.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e33.16 \u0026plusmn; 7.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.733\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"37.610619469026545%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Mental component summery (MCS)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e53.18 \u0026plusmn; 3.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e50.63 \u0026plusmn; 6.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.99410029498525%\" valign=\"top\"\u003e\n \u003cp\u003e55.17 \u0026plusmn; 16.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.4070796460177%\" valign=\"top\"\u003e\n \u003cp\u003e0.471\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eValues represent mean \u0026plusmn; standard deviation, median (interquartile range), or number (%) of cases.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"cardiac rehabilitation, telerehabilitation, cardiac surgery, exercise test, walk test, ambulatory electrocardiography monitoring","lastPublishedDoi":"10.21203/rs.3.rs-4489270/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4489270/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eTo evaluate the safety and feasibility of a remote electrocardiogram monitoring-based cardiac rehabilitation (CR) program during an early postoperative period in patients with cardiac surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eFive days after cardiac surgery, patients were referred to a CR department and participated in a low-intensity inpatient CR program. During 2 weeks of the home-based CR period after discharge, patients participated in aerobic and resistance exercises. electrocardiogram data were transmitted to a cloud where researchers closely monitored them and provided feedback to the patients via telephone calls.\u003c/p\u003e\n\u003cp\u003eGrip strength (GS), 6-min walk distance (6MWD) and self-reported questionnaires were measured at three different time points: 5 days postsurgery (T1), predischarge (T2), and 2 weeks after discharge (T3). Squat endurance tests and CPET were performed only at T2 and T3.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eSixteen patients completed the study, seven of whom underwent coronary artery bypass graft surgery (CABG). During the period between T2 and T3, peak VO2 improved from 12.39±0.57 to 17.93±1.25 mL/kg/min (p\u0026lt;0.01). The squat endurance test improved from 16.69±2.31 to 21.81±2.31 (p\u0026lt;0.01). In a comparison of values of time points between T1 and T3, the GS improved from 28.30±1.66 to 30.40±1.70 kg (p=0.02) and 6 MWD increased from 249.33±20.92 to 387.02±22.77 m (p\u0026lt;0.01). The EQ-5D and SF-36 improved from 0.59±0.03 to 0.82±0.03 (p\u0026lt;0.01) and from 83.99±3.40 to 122.82±6.06 (p\u0026lt;0.01), and KASI improved from 5.44±0.58 to 26.11±2.70 (p\u0026lt;0.01).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eEarly remote ECG monitoring-based CR programs are safe for patients who underwent cardiac surgery. Additionally, the program improved aerobic capacity, functional status, and quality of life.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration\u003c/strong\u003e: This study was registered with the Clinical Research Information Service (CRIS) under the trial registration number KCT0006444 on August 13, 2021.\u003c/p\u003e","manuscriptTitle":"Feasibility and safety of early cardiac rehabilitation using remote electrocardiogram monitoring in patients with cardiac surgery ","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-16 21:56:44","doi":"10.21203/rs.3.rs-4489270/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8a3f7e92-8d53-4b19-927a-e72ee4d914b8","owner":[],"postedDate":"July 16th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-07-26T09:10:03+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-16 21:56:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4489270","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4489270","identity":"rs-4489270","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}