Hybrid Use of Subcutaneous ICD with Other Intracardiac Devices: Two Case Reports

Hybrid Use of Subcutaneous ICD with Other Intracardiac Devices: Two Case Reports | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 30 May 2025 V1 Latest version Share on Hybrid Use of Subcutaneous ICD with Other Intracardiac Devices: Two Case Reports Authors : chen liu 0009-0007-6820-8237 , Yulong Guo , Yu Qiao , Guodong Niu , Tao Guo , and Ming peng Fu [email protected] Authors Info & Affiliations https://doi.org/10.22541/au.174858315.57087575/v1 200 views 115 downloads Contents Abstract Hybrid Use of Subcutaneous ICD with Other Intracardiac Devices: Two Case Reports Discussion and Future Prospects References Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Abstract In current clinical electrophysiology practice, some patients receiving subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation may also require additional intracardiac electronic devices due to disease complexity or therapeutic needs. However, there remains a relative lack of domestic reports on the combined use of S-ICD with cardiac resynchronization therapy (CRT) and cardiac contractility modulation (CCM). This study retrospectively summarizes the clinical course and follow-up outcomes of two patients with advanced heart failure who underwent combined implantation of S-ICD with CRT and CCM. The aim was to evaluate the feasibility, safety, and preliminary effectiveness of a multi-device hybrid strategy in specific clinical scenarios. The results demonstrated favorable technical outcomes, device compatibility, and functional performance, with no significant electromagnetic interference or device conflict. Both patients showed improved cardiac function and clinical symptoms compared to baseline. This hybrid approach offers a viable alternative for patients ineligible for traditional transvenous ICD systems—such as those with limited venous access, high infection risk, or younger age—and expands the potential indications for S-ICD in the context of multi-device therapy. It also emphasizes the clinical value of integrating hybrid device implantation into individualized arrhythmia management strategies. Hybrid Use of Subcutaneous ICD with Other Intracardiac Devices: Two Case Reports Chen Liu;Yu long Guo;Yu Qiao ; Guo dong Niu;Tao Guo;,Ming peng Fu* *Corresponding author:Fu,Ming peng,E-mail address: [email protected] Department of Cardiology,Fuwai Yumnan Cardiovascular Hospital,Kun ming 650000,China Abstract In current clinical electrophysiology practice, some patients receiving subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation may also require additional intracardiac electronic devices due to disease complexity or therapeutic needs. However, there remains a relative lack of domestic reports on the combined use of S-ICD with cardiac resynchronization therapy (CRT) and cardiac contractility modulation (CCM). This study retrospectively summarizes the clinical course and follow-up outcomes of two patients with advanced heart failure who underwent combined implantation of S-ICD with CRT and CCM. The aim was to evaluate the feasibility, safety, and preliminary effectiveness of a multi-device hybrid strategy in specific clinical scenarios. The results demonstrated favorable technical outcomes, device compatibility, and functional performance, with no significant electromagnetic interference or device conflict. Both patients showed improved cardiac function and clinical symptoms compared to baseline. This hybrid approach offers a viable alternative for patients ineligible for traditional transvenous ICD systems—such as those with limited venous access, high infection risk, or younger age—and expands the potential indications for S-ICD in the context of multi-device therapy. It also emphasizes the clinical value of integrating hybrid device implantation into individualized arrhythmia management strategies. Keywords Subcutaneous implantable cardioverter-defibrillator; cardiac contractility modulation; cardiac resynchronization therapy Introduction In modern arrhythmia management, the subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as an innovative leadless defibrillation system that does not rely on transvenous access. Comprised of a subcutaneous electrode and pulse generator, S-ICD avoids intravascular and intracardiac lead placement, thus significantly reducing the risk of complications such as infection, vascular injury, lead fracture, and tricuspid regurgitation, compared to traditional transvenous implantable cardioverter-defibrillators (TV-ICDs). S-ICD is particularly suited for select patient populations, including those without pacing indications, individuals with limited venous access, high infection risk, inherited ion channelopathies, prior infective endocarditis, younger patients, and those at high risk of sudden cardiac death. For these patients, S-ICD provides a safe and effective alternative defibrillation strategy, especially with its advantage in minimizing long-term lead-related complications. However, the absence of pacing functionality limits the standalone use of S-ICD in patients with complex heart failure or arrhythmias. In clinical practice, some patients may require additional device-based therapies—such as cardiac resynchronization therapy (CRT) or cardiac contractility modulation (CCM)—before or after S-ICD implantation to achieve optimal therapeutic outcomes. This study retrospectively presents two clinical cases of patients who received S-ICD in combination with CRT and CCM, aiming to evaluate the technical feasibility, safety, and early efficacy of hybrid device implantation in complex clinical settings, and to provide a potential reference for individualized management strategies. Case 1 A 53-year-old male presented with a two-year history of progressive exertional dyspnea and a recent episode of syncope. The patient’s medical history included chronic heart failure with recurrent ecompensation, dilated cardiomyopathy, cardiomegaly, ventricular tachycardia, paroxysmal atrial fibrillation, and hypothyroidism. Upon admission, the patient exhibited the following vital signs: temperature 36.6°C, heart rate 60 bpm, respiratory rate 20 breaths per minute, and blood pressure 94/63 mmHg. Physical examination revealed clear lung fields, an enlarged cardiac silhouette, a regular rhythm with a diastolic murmur at the left sternal border (third intercostal space), and no peripheral edema. Twenty days prior to admission, Holter monitoring revealed sustained ventricular tachycardia, resulting in syncope. Transthoracic echocardiography showed a left atrial diameter of 41 mm, a left ventricular end-diastolic diameter (LVEDD) of 74 mm, and a severely reduced left ventricular ejection fraction (LVEF) of 21%, consistent with marked ventricular dilation and impaired systolic function. According to the 2021 Chinese Expert Consensus on the Clinical Application of Implantable Cardioverter-Defibrillators, the patient met Class I indications for ICD implantation. To avoid complications associated with transvenous systems— including vascular injury, lead fracture, infection, and tricuspid regurgitation—a subcutaneous ICD (S-ICD) was selected. After ruling out contraindications and obtaining informed consent, the device was successfully implanted on hospital day 2 (April 22, 2022). Postoperative management included guideline-directed medical therapy (GDMT) with sacubitril/valsartan, dronedarone, furosemide, potassium chloride, spironolactone, and dapagliflozin. However, the patient continued to experience symptomatic heart failure and was readmitted approximately one month after discharge. Although the patient did not meet criteria for cardiac resynchronization therapy (CRT), pharmacologic therapy alone proved ineffective. To address ongoing symptoms and reverse ventricular remodeling, a cardiac contractility modulation (CCM) device was implanted on June 1, 2022. Follow-up revealed one inappropriate S-ICD shock due to double counting, which was corrected through device reprogramming. CCM function was stable with a delivery rate of 99%. Echocardiography on September 27, 2023, showed LA 44 mm, LVEDD 65 mm, and LVEF improved to 36%. The patient’s heart failure symptoms were significantly improved, with reduction in chamber size and improved systolic function. Figures 1:Postoperative ECG Figure 2: Postoperative chest X-ray Case 2 A 26-year-old male patient was admitted with a 26-year history of recurrent palpitations and a 16-year history of intermittent syncope, with worsening symptoms over the previous two weeks. His medical history included chronic heart failure, dilated cardiomyopathy, non-sustained ventricular tachycardia (NSVT), frequent premature ventricular contractions (PVCs), hepatic and renal dysfunction, and prior implantation of a cardiac resynchronization therapy pacemaker (CRT-P). On admission, his vital signs were: temperature 36.1 °C, heart rate 92 bpm, respiratory rate 19 breaths/min, and blood pressure 117/81 mmHg. He was alert and able to sit independently. Lung auscultation revealed clear breath sounds without rales. Cardiac exam showed enlargement with a regular rhythm at 92 bpm and no murmurs. No peripheral edema was noted. The patient had previously received CRT-P due to economic constraints, despite indications for defibrillator therapy. Transthoracic echocardiography revealed a left atrial diameter of 46 mm, a LVEDD of 80 mm, and a reduced LVEF of 25%. The left ventricle exhibited a spherical morphology, and moderate mitral regurgitation was attributed to leaflet malcoaptation. Device interrogation indicated that recurrent syncope was temporally associated with NSVT. According to the 2021 Chinese Expert Consensus, the patient was eligible for ICD therapy. After ruling out contraindications and obtaining informed consent, a subcutaneous ICD (S-ICD) was successfully implanted on November 23, 2023. Postoperative follow-up demonstrated appropriate device function. One episode of ventricular tachycardia was appropriately detected and terminated by the S-ICD. Heart failure symptoms and clinical stability improved. Figures 3: A, Preoperative ECG.B,Postoperative ECG Figure 2: Postoperative chest X-ray Discussion and Future Prospects As an innovative technology in the field of cardiac treatment, S-ICDs have gained increasing clinical adoption in recent years. Relevant studies have shown that compared with traditional transvenous implantable cardioverter defibrillators (TV-ICDs), S-ICDs do not require a transvenous pathway, and reduce complications including lead failure, infection, thrombosis, and tricuspid valve injury. thus enhancing patient safety and quality of life [1-3]. However, S-ICDs lack a pacing function, which limits their scope of application. Therefore, it is essential to explore the hybrid use of S-ICDs and intracardiac electronic devices to optimize the treatment of patients with heart disease. 3.1. Advantages of Hybrid Use The subcutaneous implantation of an S-ICD offers several advantages over traditional transvenous implantable cardioverter defibrillators (ICDs). It avoids complications such as infection, lead breakage, and endocarditis associated with transvenous ICD leads, thereby decreasing surgical risks and reducing operation time. Moreover, it eliminates direct contact with the heart, reducing risks such as cardiac perforation and pericardial effusion, and diminishes patient discomfort or the sensation of a foreign body. [4] Research indicates that patients younger than 60 are more likely to receive S-ICD implants following the removal of failed leads than in a multicenter Italian study by Viani et al. [5]. Younger patients, in particular, are more inclined to opt for S-ICDs after the removal of transvenous ICDs, especially if the removal is due to infection. For patients who already have intracardiac electronic devices but still require defibrillation protection, the combination of S-ICDs with intracardiac devices represents a novel treatment strategy. This approach avoids the removal or replacement of existing devices, thus alleviating patient pain and reducing economic burden. Furthermore, S-ICDs are compatible with various cardiac implants, offering clinicians a broad range of treatment options. Additionally, patients can enjoy daily activities such as exercise and bathing with fewer restrictions, thus enhancing their overall quality of life. 3.2. Challenges Faced by Hybrid Applications and Experience Sharing 3.2.1. Combination of S-ICD and CCM Currently, the implantation technology of S-ICD has reached a relatively mature stage and is increasingly being applied clinically. However, the combination of S-ICDs with other electronic implantable devices in the heart remains a relatively new field. Therefore, it is essential to have a profound understanding of the characteristics of intracardiac electronic devices to ensure that they synergize with S-ICDs in vivo for optimal therapeutic outcomes. As illustrated in a previous case, the combining S-ICD with CCM or CRT presents a novel therapeutic option for advanced heart failure. CCM provides stimulation during the absolute refractory phase, improves ventricular contractility and alleviates symptoms. This strategy reduces sudden cardiac death risk and improves clinical outcomes and enhances quality of life, offering dual therapeutic protection. Nonetheless, in practice, the sensing mode of S-ICDs differs from that of traditional transvenous ICDs, relying more on morphological discrimination of body surface signals. Consequently, when CCM is active, it emits a series of strong stimulation signals with a high voltage and wide pulse width during the absolute refractory period of the QRS wave, altering the QRS morphology and potentially causing S-ICDs to misinterpret these as ventricular arrhythmias, thereby triggering unnecessary defibrillation. To minimize the occurrence of such events, the CCM output voltage can be gradually decreased—for instance, titrating the voltage from 7.5 V to 4.0 V—to effectively prevent S-ICD from misinterpreting CCM signals. Furthermore, CCM and S-ICD undergo cross-sensing testing during implant surgery to ensure that they function in unison, correctly distinguishing and responding to both normal and abnormal cardiac rhythms. Defibrillation threshold testing was also conducted during S-ICD implantation to confirm the device’s accurate sensing and differentiation of ventricular fibrillation. 3.2.2. The combined use of S-ICDs and CRT has been shown to reduce the risk of sudden cardiac death (SCD) by improving the mechanical and electrophysiological properties of the heart, enhancing left and right ventricular synchrony, and improving cardiac function, thereby reducing the occurrence of ventricular arrhythmia. However, clinical practice indicates that SCD may still occur in some patients even after CRT. Therefore, a combination of S-ICD and CRT may exist, which has been proven to significantly reduce the risk of SCD in patients with heart failure and provide more treatment options for patients with decreased cardiac function. To maximize the therapeutic effect of the combination of CRT and S-ICD, our center’s experience is as follows. First, based on the latest guidelines and expert consensus, combined with the patient’s clinical symptoms, cardiac function, arrhythmia type, and cardiac structure, among other factors, we screened patients suitable for CRT-D, especially those with a higher risk of sudden death. In-depth communication between physicians and patients is also required to fully understand the potential risks and benefits of CRT implantation and to make informed decisions. Second, prior to implantation of the S-ICD, the patient must be screened for three ECG vectors generated in the supine position (required) and standing/sitting position to ensure that at least one vector has a QRS and T wave morphology that conforms to the preset template range in all positions and that the ratio of R wave to T wave is greater than 2.5:1. This approach significantly reduces the risk of inappropriate shocks and lead displacement. Finally, to improve the defibrillation success rate and effectively reduce the interference with cardiac resynchronization therapy (CRT), according to the PRATORIAN scoring system, the implanted lead and defibrillator case should be positioned as close to the chest wall as possible during S-ICD implantation, while ensuring that the defibrillator case is positioned posterior to the midaxillary line. Patients undergoing CRT implantation generally have a history of cardiac enlargement, insufficiency, and malignant arrhythmias. S-ICD implantation in such patients may be associated with higher surgical and anesthetic risk. More detailed and comprehensive evaluation of patients before surgery and more cautious operational measures during surgery are required to reduce the risk of complications. In summary, the combination of SICD with CCM and CRT is feasible. Maximizing efficacy requires appropriate patient selection, skilled implantation, and comprehensive follow-up and necessitates comprehensive long-term management. We need to strengthen patient education, fully understand the synergistic effects of these devices and their potential risks, enhance self-management capabilities, and regularly monitor the patient’s disease progression and device performance to ensure proper functioning and meet treatment needs. Multidisciplinary team evaluations should be organized on a regular basis to ensure individualized and precise treatment options, maximize treatment effects, and optimize patients’ quality of life. In addition, it is necessary to establish a robust follow-up system to regularly assess the psychological state of patients and provide necessary psychological support to foster long-term psychological resilience during long-term treatment. Through comprehensive management, patient compliance is effectively improved; the risk of treatment interruption is reduced; and the sustainability, stability, and safety of the overall treatment effect are ensured. 3. Future Prospects At present, the S-ICD system only has a defibrillation function, but a leadless pacemaker can provide a pacing function for the S-ICD. With ongoing advances, combining S-ICDs and leadless pacemakers will likely become feasible, further broadening the scope of application of S-ICDs and providing more comprehensive and personalized treatment for patients. In summary, the hybrid use of S-ICDs and intracardiac electronic devices provides a variety of personalized treatment options for patients requiring electronic implants, both to provide their respective advantages and to compensate for each other’s shortcomings. Therefore, the feasibility and safety of the hybrid use of S-ICDs and intracardiac implanted electronic devices should be comprehensively evaluated before surgery, including disease conditions, imaging examinations, and electrophysiological tests, to ensure compatibility between the two devices. In addition, close monitoring and regular follow-up are essential to ensure patient safety and normal use of the device. Through these comprehensive assessment and management measures, risks can be minimized and the quality of life of patients can be improved. In the future, with the continuous advancement of technology and accumulation of clinical experience, the hybrid use of S-ICDs and intracardiac electronic devices will play a more important role in the field of intracardiac electronic implant therapy, resulting in better treatment results and more effective improvement of quality of life for more patients. Acknowledgments / Funding Support This work was supported by the following grants: - Yunnan Provincial Key Research and Development Program – Research, Development, and Application Project of a Cardiovascular Remote Monitoring and Emergency Rescue System Based on Artificial Intelligence and Big Data Information Platform (Project No. 202103AC100002); - Yunnan Provincial Department of Science and Technology Science and Technology Plan Project (Project No. 202103AC100004); - Scientific Research Fund of Fuwai Yunnan Cardiovascular Hospital (Project No. 2019YFKT-09); - Scientific Research Fund of the Yunnan Provincial Department of Education (Project No. 2019J1302). Conflict of Interest The authors declare no conflicts of interest related to this manuscript. References 1. 1. Gold MR, Lambiase PD, El-Chami MF, et al. Primary results from the UNTOUCHED trial: Understanding Outcomes with the S-ICD in Primary Prevention Patients with Low Ejection Fraction. Circulation. 2021;143(1):7–17. 2. Rordorf R, Casula M, Pezza L, et al. Subcutaneous versus transvenous implantable defibrillators: an updated meta-analysis. Heart Rhythm. 2021;18(3):382–391. 3. Chinese Society of Cardiology; Electrophysiology and Pacing Section, Chinese Medical Doctor Association; Cardiac Rhythm Management Professional Committee. Chinese Expert Consensus on Totally Subcutaneous Implantable Cardioverter Defibrillators (2023). Chinese Journal of Cardiac Arrhythmias. 2023;27(5):376–389. 4. Yuan C, Zeng F, Li D, et al. Clinical outcomes following the implantation of a totally subcutaneous implantable cardioverter-defibrillator after the removal of intravenous leads. Chinese Circulation Journal. 2024;39(8):781–784. 5. Viani S, Migliore F, Tola G, et al. Use and outcomes of subcutaneous implantable cardioverter-defibrillator (ICD) after transvenous ICD extraction: an analysis of current clinical practice and comparison with transvenous ICD reimplantation. Heart Rhythm. 2019;16(4):564–571. Google Scholar Information & Authors Information Version history V1 Version 1 30 May 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords basic: cardiac fibrillation/defibrillation clinical: electrophysiology – conduction disturbances Authors Affiliations chen liu 0009-0007-6820-8237 Fuwai Yunnan Cardiovascular Hospital View all articles by this author Yulong Guo Fuwai Yunnan Cardiovascular Hospital View all articles by this author Yu Qiao Fuwai Yunnan Cardiovascular Hospital View all articles by this author Guodong Niu Fuwai Yunnan Cardiovascular Hospital View all articles by this author Tao Guo Fuwai Yunnan Cardiovascular Hospital View all articles by this author Ming peng Fu [email protected] Fuwai Yunnan Cardiovascular Hospital View all articles by this author Metrics & Citations Metrics Article Usage 200 views 115 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation chen liu, Yulong Guo, Yu Qiao, et al. 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