Septal Thickness as a Predictor for Appropriate ICD Shocks in Hypertrophic Cardiomyopathy Patients

Septal Thickness as a Predictor for Appropriate ICD Shocks in Hypertrophic Cardiomyopathy Patients | 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 Septal Thickness as a Predictor for Appropriate ICD Shocks in Hypertrophic Cardiomyopathy Patients Sina Danesh, Mahsa Ahadi, Mohammad Hossein Nikoo This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5391709/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 Introduction: implantable cardioverter defibrillators (ICD) can prevent sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) patients. Guidelines assess HCM patients regarding SCD risk to identify ICD candidates. This study aimed to evaluate the correlation between receiving an appropriate shock and SCD’s main risk factors in patients with ICD. Method All the HCM patients with ICD implantations during 2006 to 2021 in Alzahra and Shahid Faghihi hospitals in Shiraz, Iran who were ≥ 18 were included. Patients with other cardiac or chronic underlying diseases were excluded. Patients were divided into two groups based on receiving an appropriate or inappropriate shock. We used Pearson correlation test to find correlations between receiving an appropriate shock and cardinal risk factors of SCD. A receiver operating characteristic curve was plotted to define a cutoff point for the variables that were correlated to appropriate shock. Result We enrolled 71 patients (65% male). The mean age of participants was 46.0 ± 17.5 years. Patients who experienced an appropriate shock during the follow-up period (24 patients), were younger (41.3 ± 13.3 years). Only septal thickness of > 18mm showed a significant correlation with receiving an appropriate shock with 87.5% sensitivity and 86% specificity (all P values < 0.001). The mortality rate in our population was 5.6%. Conclusion conventional risk factors of SCD have a low predictive utility for appropriate shocks. The latest guidelines state that left ventricle wall thickness ≥ 30 mm is an isolated risk factor. We suggest the septal thickness > 18mm as a potential risk factor in SCD risk assessment guidelines. Cardiac & Cardiovascular Systems Defibrillators Implantable Death Sudden Cardiac Cardiomyopathy Hypertrophic Figures Figure 1 Introduction Sudden cardiac death (SCD) is one of the grimmest results of hypertrophic cardiomyopathy (HCM), which usually happens Consecutive to fatal ventricular tachyarrhythmia (VT) ( 1 – 3 ). An implantable cardioverter-defibrillator (ICD) can effectively prevent SCDs resulting from these arrhythmias; however, Inappropriate ICD shocks are not uncommon ( 4 , 5 ), and besides all the physical and psychological side effects, shocks – appropriate or not- are associated with increased all-cause mortality ( 6 ). Therefore, physicians must choose ICD candidates very carefully to avoid unnecessary ICD implantation, reduce the adverse effects to a minimum, and ensure that as many patients who can benefit from this treatment will receive it ( 7 ). Cardiologists use specific guidelines to decide whether a patient will benefit from an ICD. The systematic enhanced guideline by American College of Cardiology and American Heart Association (ACC/AHA) predicts SCD risk with very high sensitivity ( 8 ). It suggests that family history of SCD in first-degree relatives, unexplained syncope, or left ventricular (LV) wall thickness ≥ 30 can solely be enough to consider ICD implantation for a patient. Still, the European Society of Cardiology (ESC) guideline recommends ICD for patients in the presence of two or more risk factors ( 7 ) and has justified concerns about over-treatment ( 9 , 10 ). These guidelines also assess other risk factors like prior documented cardiac arrest, ventricular fibrillation, or hemodynamically significant VT, left atrial diameter, age, unstable ventricular tachycardia (NSVT) in ECG Holter monitoring, left ventricular outflow tract obstruction (LVOTO), and hypotensive response to exercise ( 11 – 16 ). Mentioned guidelines help us roughly identify HCM patients in danger of SCD ( 17 ); Still, The heterogeneous nature of this disease and multiple factors that affect its outcome are responsible for disagreements regarding HCM patients’ management ( 7 ). Although scientists have come a long way in developing the risk stratification strategies during past decades, More studies are necessary to further assess every risk factor in these algorithms ( 7 ). This study aimed to evaluate the correlation between receiving an appropriate shock and SCD’s main risk factors in HCM patients with ICD. Methods Study design This is a retrospective cross-sectional study conducted in Alzahra and Shahid Faghihi hospitals, Shiraz, Iran, from 2006 to 2021. All the patients diagnosed with HCM who underwent ICD implantation during this interval were enrolled. Inclusion criteria were clinical diagnosis of HCM based on two-dimensional echocardiography, having an ICD, and age ≥ 18 years. Patients who had any other cardiac or chronic underlying disease were excluded. Data extraction Demographic Information (age and gender), type of ICD, age at the time of implantation, ejection fraction (EF), septal thickness (mm), and patients’ contact numbers were obtained from patient files. We conducted a telephone survey of the patients (or their caretakers) based on a researcher-made questionnaire. The questionnaire contained queries about family history of SCD, receiving an ICD shock, complications of ICD implantation (including lead disconnection or breakage, wire displacements, electric shock, CVA and Left side hemiplegia, unexplained syncope, wound infection, need for another ICD implantation, history of myectomy, and death of the patient). We also asked them to send us their medical records, including an ICD shock analysis sheet that our patients are provided with by their cardiologist every time they receive a shock. We divided our patients into two groups based on receiving an appropriate or inappropriate shock. Variables were compared between these two groups. Informed consent was obtained from all subjects and/or their legal guardians. Patients who did not consent or send their medical records were excluded from the study. Statistical analysis We described our variables using mean ± standard deviation or number (%) when needed. We used chi-square and student t-test to find any statistically significant difference between the two groups regarding their baseline characteristics. Pearson correlation test was used to find correlations between receiving an appropriate shock and variables like septal thickness, EF, syncope, family history of SCD, and previous myectomy. Then we plotted a receiver operating characteristic (ROC) curve to define a cutoff point for variables that were shown to correlate with appropriate shock. two-tailed p-value ≤ 0.05 was considered significant. SPSS version 16 was used for all analyses. Ethics considerations This study was conducted in accordance with the declaration of Helsinki( 38 ), and was approved by the institutional review board and ethics committee of Shiraz university of medical sciences with ethics number of IR.SUMS.MED.REC.1400.555. Results Seventy-one patients entered this study based on the inclusion and exclusion criteria. Sixty-two patients had undergone ICD implantation for primary prevention. The male to female ratio was 1.8:1. The mean age of participants was 46.0 ± 17.5 years. All the study population were on beta-blockers. Twenty-four patients (33.8%) experienced an appropriate shock during our follow-up period. These patients were generally younger, with a mean age of 41.3 ± 13.3 years versus 48.4 ± 19.1 years in the group who received inappropriate shocks (p-value = 0.035). The overall mean of septal thickness was 19.3 ± 9.9 mm. patients who received appropriate shocks had a septal thickness of 28.6 ± 9.0 mm. Still, the mean septal thickness in patients who did not receive appropriate shocks was 14.3 ± 5.9 mm. (p-value < 0.001). The mean ejection fraction in both groups was similar and approximately 52%. (P-value = 0.93). Most of our study population had dual-chamber ICDs. (Table 1 ). Table 1 Demographic and clinical characteristics of the study population Variables Appropriate shock(n = 24) Inappropriate shock or not receiving a shock (n = 47) Total (n = 71) Gender (N) Male 16 30 46 Female 8 17 25 Age (Y) (Mean ± SD) 41.3 ± 13.3 48.4 ± 19.1 46.0 ± 17.5 Septal thickness (mm) (Mean ± SD) 28.6 ± 9.0 14.3 ± 5.9 19.3 ± 9.9 EF (%) (Mean ± SD) 52.2 ± 8.0 52.0 ± 13.6 52.0 ± 11.8 Positive Previous history (N) Septal myectomy 7 5 12 family history of SCD 6 11 17 previous ICD insertion 6 3 9 ICD implant types (N) Single chamber ICD 9 12 21 Dual-chamber ICD 15 34 49 Biventricular 0 1 1 Table 2 demonstrates our patients' mortality and side effects of ICD implantation. Most of our study population had no side effects. But the main complications were unexplained syncope and lead-related problems, including disconnected leads, wire displacements, and lead breakage. Two of our patients died of decompensated heart failure, one from stroke and one from myocardial infarction. Table 2 Mortality and side effects of ICD implantation in the study population* Appropriate shock (n = 24) Inappropriate shock or not receiving a shock (n = 47) Total (n = 71) Without side effects 18 38 56 Lead related complications 6 2 8 Electric shock and shock mode 0 2 2 CVA and Left side hemiplegia 0 1 1 Unexplained syncope 2 7 9 Death 0 4 4 *some patients had experienced more than one complication, so the sum of each column exceeds the group size. We conducted a Pearson correlation test between receiving an appropriate shock and variables like septal thickness, EF, syncope, family history of SCD, and previous myectomy. The only factor that showed a significant correlation with receiving an appropriate shock was septal thickness among the evaluated variables. (P value < 0.001) (Table 3 ). Table 3 Pearson correlations between appropriate shock and evaluated variables Appropriate shock P-value Septal thickness 0.7 < 0.001 EF 0.01 0.93 Unexplained Syncope -0111 0.37 Myectomy 0.22 0.07 Positive family history of SCD 0.05 0.71 We plotted a ROC curve to find the most sensitive and specific cutoff value for the septal thickness that correlates with an appropriate shock. Our analysis showed that septal thickness of greater than 18 mm had the most desirable sensitivity (87.5%) and specificity (86%) (P-value < 0.001). The area under curve is 0.895 (95% Confidence interval 0.796 to 0.957), which shows excellent accuracy of this cutoff point. (Fig. 1 ) Discussion In this retrospective study, we analyzed the correlation between receiving an appropriate ICD shock and variables reported to predict SCD, such as EF, family history of sudden death, LV wall thickness, and recent unexplained syncope ( 18 ). Of these evaluated variables, only septal thickness showed statistical significance. We then defined the cutoff value of > 18 mm for the septal thickness with optimal sensitivity and specificity in predicting appropriate ICD interventions. We also observed that the patients who received an appropriate shock were significantly younger than those who did not at the time of ICD implantation. ICD implantation is the only effective treatment that can prevent SCD in HCM patients ( 7 ). Still, there are controversies regarding its indications, efficacy, and possible downsides like device complications and inappropriate shocks ( 8 , 19 ). In our study, 24 out of 71 received an appropriate shock over 15 years (2.25%/y). This data aligns with the most recent studies that report appropriate ICD shock occurrence to be 2.3%/y – 4.9%/y ( 20 – 23 ). A meta-analysis conducted in 2012 reported an appropriate shock rate of 3.3%/year and a low mortality rate following ICD implantation ( 4 ). Also, Maron et al. suggest that ICD interventions, especially in primary prevention, are highly effective, and patients with only one risk factor should be considered for ICD implantation ( 22 ). However, inappropriate shocks might happen in about 20% of patients, and every inappropriate shock can increase mortality ( 5 , 24 ). Also, ICD complications are not negligible ( 7 , 22 , 25 ). Further research is needed to find more accurate predictors of appropriate shocks ( 21 ). In this study, we found no correlation between appropriate shocks and risk factors like EF, family history of SCD, and recent unexplained syncope. Still, our data demonstrated an association between appropriate ICD intervention and septal thickness. Previous studies report a low predictive utility of the conventional risk factors for appropriate shocks (i.e., age, EF, severe LVH, NSVT, atrial fibrillation, recent unexplained syncope, and family history of SCD) ( 7 , 20 , 26 – 28 ). The significance level for the correlation of appropriate shocks and conventional risk factors is estimated to be 15% ( 7 , 17 ). Despite these risk factors' low positive predictive accuracy, they have remarkable negative predictive accuracy ( 18 , 29 ). More recent data demonstrate that severe late gadolinium enhancement in MRI before ICD implantation, left atrial volume index (LAVI), and global longitudinal strain could predict appropriate ICD shocks more accurately than other risk factors ( 20 , 21 ). Maron et al. showed that the risk of SCD had a direct correlation with wall thickness as the cumulative risk of death in 20 year period for thickness < 20mm is negligible, but approximately 40% for wall thickness ≥ 30 mm. the magnitude of hypertrophy directly and independently predicts HCM prognosis ( 14 , 30 ). The latest ACC/AHA guideline suggests that LV wall thickness ≥ 30 mm should be considered an isolated risk factor ( 7 , 16 ); on the other hand, Olivetti et al. stated the exact opposite. Their result showed no correlation between the extent of LV hypertrophy and cardiovascular mortality in HCM patients unless detected at a very young age ( 31 ). Our study demonstrated that septal thickness significantly correlated with receiving an appropriate shock. However, our analysis showed that a septal thickness of > 18 mm rather than ≥ 30 mm can predict appropriate shocks more accurately. A septal thickness of more than 18mm has 87.5% sensitivity and 86% specificity. The decision-making about ICD implantation must be individualized for each patient and based on their condition. Still, this new cutoff value used in the context of the most recent guidelines, can help physicians to be more selective and accurate. We observed that the patients who received appropriate shock were significantly younger than those who did not, with a mean age difference of approximately seven years (41.3 ± 13.3 versus 48.4 ± 19.1). Previous studies reported that SCD mostly happens in younger patients but is not confined to them ( 1 , 32 , 33 ). Also, age affects the significance of other risk factors ( 7 ). Our observation regarding this matter aligns with the theory that SCD mainly occurs in younger patients. Generally, about 35–40% of patients suffer from ICD complications ( 34 , 35 ). A meta-analysis evaluating 16 cohort studies reported the annualized rate of complications related to ICDs to be 3.4% ( 4 ). About 21% of our patients reported complications after ICD implantation. Unexplained syncope (13%) and Problems related to the defibrillator leads (11%) comprised most of our complications. A 2020 study showed that infection, lead fracture, and lead displacement occurred in 12% of their patients. ( 36 ) The mortality rate in our population was 5.6% (4 out of 71) over 15 years (0.37%/y). The Schinke meta-analysis reported annualized cardiac mortality rate of 0.6% ( 4 ). Maron points out that despite heart failure patients, ICD discharges are not associated with a significant increase in mortality and morbidity in HCM patients ( 23 ). Aside from expected side effects, studies show that every ICD shock can cause a small degree of myocardial damage which can cause a transient troponin rise. Increased mortality in ICD patients after receiving a shock can result from this myocardial damage or an indicator of an overall worse cardiac condition ( 37 ). This study evaluated HCM patients with ICD over a 15-year interval, which helped us include patients who received ICD shocks long after their operation. This is also the first time that the cutoff value of > 18 mm has been introduced for predicting appropriate shocks. This study is limited by its population as we selected them from only two centers in the south of Iran. More research with larger study populations is necessary to evaluate this matter further. Conclusion ICD implantation has indeed expanded the life span of HCM patients. The risk stratification of SCD in these patients is constantly evolving and changing for the better. We suggest the consideration of septal thickness > 18 mm as a potential predictor for appropriate ICD shocks in SCD risk assessment guidelines. Most HCM patients exposed to SCD are generally younger, and maintaining these patients' quality of life is crucial. Therefore physicians should assess every patient individually and precisely regarding ICD implantation. They should be and keep up with the latest findings to reduce the number of inappropriate shocks to the smallest number possible. Declarations Data availability The data of the current study is available from the corresponding author on reasonable request. Contributions S.D. contributed to the conception, participated in data interpretation and assisted in drafting the manuscript. M.A. analyzed the data and drafted the manuscript. M.H.N. designed the study, supervised the study, and critically revised the manuscript. All authors red and approved the final manuscript. Corresponding author Correspondence to Mohammad Hossein Nikoo. Ethics declaration This study was conducted in accordance with the declaration of Helsinki(38), and was approved by the institutional review board and ethics committee of Shiraz university of medical sciences with ethics number of IR.SUMS.MED.REC.1400.555. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5391709","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":374140382,"identity":"84529b92-6157-4be4-82e9-bcd91c9f8556","order_by":0,"name":"Sina Danesh","email":"","orcid":"https://orcid.org/0000-0002-4042-417X","institution":"Shiraz University of medical science","correspondingAuthor":false,"prefix":"","firstName":"Sina","middleName":"","lastName":"Danesh","suffix":""},{"id":374140384,"identity":"1e18eb27-745d-4b7c-87a3-e05ad51cd163","order_by":1,"name":"Mahsa Ahadi","email":"","orcid":"https://orcid.org/0000-0002-6111-2706","institution":"Shiraz University of medical science","correspondingAuthor":false,"prefix":"","firstName":"Mahsa","middleName":"","lastName":"Ahadi","suffix":""},{"id":374140385,"identity":"48fc6af9-eefa-4845-be51-49a742e4b20c","order_by":2,"name":"Mohammad Hossein Nikoo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAmUlEQVRIiWNgGAWjYDACCRBRwcBgQKKWMyRrYWwjRYvu7N6jmwvnHZY3Z28+wPCjYhthLWZ3zqXdnrntsOHOnmMJjD1nbhOh5UaO2W3ebYcZN9zIMWBmbCNay5zD9qRqaTicSKKWGcfSkzecOZZwkHi/FNRY22443nzwwY8KIrSAADMDQzOYcYA49RAtdUQrHgWjYBSMghEIAJLkQhD+srcWAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0001-8338-094X","institution":"Shiraz University of medical science","correspondingAuthor":true,"prefix":"","firstName":"Mohammad","middleName":"Hossein","lastName":"Nikoo","suffix":""}],"badges":[],"createdAt":"2024-11-05 03:18:30","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-5391709/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5391709/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":68355231,"identity":"cd0093db-3044-48f8-836e-72b8afbcc5fa","added_by":"auto","created_at":"2024-11-06 11:16:13","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":37468,"visible":true,"origin":"","legend":"\u003cp\u003eThe ROC curve demonstrates the relationship between clinical sensitivity and specificity for every septal thickness and receiving an appropriate shock.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5391709/v1/c266e308abf173fa5c5948b8.png"},{"id":68355245,"identity":"7fd047bd-75c1-4b01-af46-198fddca27ab","added_by":"auto","created_at":"2024-11-06 11:16:18","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":439843,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5391709/v1/d93f0984-b7e5-4dff-a77a-a51c26c703d4.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eSeptal Thickness as a Predictor for Appropriate ICD Shocks in Hypertrophic Cardiomyopathy Patients\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSudden cardiac death (SCD) is one of the grimmest results of hypertrophic cardiomyopathy (HCM), which usually happens Consecutive to fatal ventricular tachyarrhythmia (VT) (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). An implantable cardioverter-defibrillator (ICD) can effectively prevent SCDs resulting from these arrhythmias; however, Inappropriate ICD shocks are not uncommon (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e), and besides all the physical and psychological side effects, shocks \u0026ndash; appropriate or not- are associated with increased all-cause mortality (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Therefore, physicians must choose ICD candidates very carefully to avoid unnecessary ICD implantation, reduce the adverse effects to a minimum, and ensure that as many patients who can benefit from this treatment will receive it (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e Cardiologists use specific guidelines to decide whether a patient will benefit from an ICD. The systematic enhanced guideline by American College of Cardiology and American Heart Association (ACC/AHA) predicts SCD risk with very high sensitivity (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). It suggests that family history of SCD in first-degree relatives, unexplained syncope, or left ventricular (LV) wall thickness\u0026thinsp;\u0026ge;\u0026thinsp;30 can solely be enough to consider ICD implantation for a patient. Still, the European Society of Cardiology (ESC) guideline recommends ICD for patients in the presence of two or more risk factors (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e) and has justified concerns about over-treatment (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). These guidelines also assess other risk factors like prior documented cardiac arrest, ventricular fibrillation, or hemodynamically significant VT, left atrial diameter, age, unstable ventricular tachycardia (NSVT) in ECG Holter monitoring, left ventricular outflow tract obstruction (LVOTO), and hypotensive response to exercise (\u003cspan additionalcitationids=\"CR12 CR13 CR14 CR15\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMentioned guidelines help us roughly identify HCM patients in danger of SCD (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e); Still, The heterogeneous nature of this disease and multiple factors that affect its outcome are responsible for disagreements regarding HCM patients\u0026rsquo; management (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Although scientists have come a long way in developing the risk stratification strategies during past decades, More studies are necessary to further assess every risk factor in these algorithms (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). This study aimed to evaluate the correlation between receiving an appropriate shock and SCD\u0026rsquo;s main risk factors in HCM patients with ICD.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design\u003c/h2\u003e \u003cp\u003eThis is a retrospective cross-sectional study conducted in Alzahra and Shahid Faghihi hospitals, Shiraz, Iran, from 2006 to 2021. All the patients diagnosed with HCM who underwent ICD implantation during this interval were enrolled. Inclusion criteria were clinical diagnosis of HCM based on two-dimensional echocardiography, having an ICD, and age\u0026thinsp;\u0026ge;\u0026thinsp;18 years. Patients who had any other cardiac or chronic underlying disease were excluded.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eData extraction\u003c/h3\u003e\n\u003cp\u003eDemographic Information (age and gender), type of ICD, age at the time of implantation, ejection fraction (EF), septal thickness (mm), and patients\u0026rsquo; contact numbers were obtained from patient files. We conducted a telephone survey of the patients (or their caretakers) based on a researcher-made questionnaire. The questionnaire contained queries about family history of SCD, receiving an ICD shock, complications of ICD implantation (including lead disconnection or breakage, wire displacements, electric shock, CVA and Left side hemiplegia, unexplained syncope, wound infection, need for another ICD implantation, history of myectomy, and death of the patient). We also asked them to send us their medical records, including an ICD shock analysis sheet that our patients are provided with by their cardiologist every time they receive a shock. We divided our patients into two groups based on receiving an appropriate or inappropriate shock. Variables were compared between these two groups. Informed consent was obtained from all subjects and/or their legal guardians. Patients who did not consent or send their medical records were excluded from the study.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eWe described our variables using mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation or number (%) when needed. We used chi-square and student t-test to find any statistically significant difference between the two groups regarding their baseline characteristics. Pearson correlation test was used to find correlations between receiving an appropriate shock and variables like septal thickness, EF, syncope, family history of SCD, and previous myectomy. Then we plotted a receiver operating characteristic (ROC) curve to define a cutoff point for variables that were shown to correlate with appropriate shock. two-tailed p-value\u0026thinsp;\u0026le;\u0026thinsp;0.05 was considered significant. SPSS version 16 was used for all analyses.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEthics considerations\u003c/h3\u003e\n\u003cp\u003eThis study was conducted in accordance with the declaration of Helsinki(\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e), and was approved by the institutional review board and ethics committee of Shiraz university of medical sciences with ethics number of IR.SUMS.MED.REC.1400.555.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eSeventy-one patients entered this study based on the inclusion and exclusion criteria. Sixty-two patients had undergone ICD implantation for primary prevention. The male to female ratio was 1.8:1. The mean age of participants was 46.0\u0026thinsp;\u0026plusmn;\u0026thinsp;17.5 years. All the study population were on beta-blockers. Twenty-four patients (33.8%) experienced an appropriate shock during our follow-up period. These patients were generally younger, with a mean age of 41.3\u0026thinsp;\u0026plusmn;\u0026thinsp;13.3 years versus 48.4\u0026thinsp;\u0026plusmn;\u0026thinsp;19.1 years in the group who received inappropriate shocks (p-value\u0026thinsp;=\u0026thinsp;0.035). The overall mean of septal thickness was 19.3\u0026thinsp;\u0026plusmn;\u0026thinsp;9.9 mm. patients who received appropriate shocks had a septal thickness of 28.6\u0026thinsp;\u0026plusmn;\u0026thinsp;9.0 mm. Still, the mean septal thickness in patients who did not receive appropriate shocks was 14.3\u0026thinsp;\u0026plusmn;\u0026thinsp;5.9 mm. (p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The mean ejection fraction in both groups was similar and approximately 52%. (P-value\u0026thinsp;=\u0026thinsp;0.93). Most of our study population had dual-chamber ICDs. (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic and clinical characteristics of the study population\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAppropriate shock(n\u0026thinsp;=\u0026thinsp;24)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eInappropriate shock or not receiving a shock (n\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTotal (n\u0026thinsp;=\u0026thinsp;71)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender (N)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (Y) (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41.3\u0026thinsp;\u0026plusmn;\u0026thinsp;13.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e48.4\u0026thinsp;\u0026plusmn;\u0026thinsp;19.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e46.0\u0026thinsp;\u0026plusmn;\u0026thinsp;17.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSeptal thickness (mm) (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.6\u0026thinsp;\u0026plusmn;\u0026thinsp;9.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.3\u0026thinsp;\u0026plusmn;\u0026thinsp;5.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19.3\u0026thinsp;\u0026plusmn;\u0026thinsp;9.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEF (%) (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e52.2\u0026thinsp;\u0026plusmn;\u0026thinsp;8.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e52.0\u0026thinsp;\u0026plusmn;\u0026thinsp;13.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e52.0\u0026thinsp;\u0026plusmn;\u0026thinsp;11.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePositive Previous history (N)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSeptal myectomy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003efamily history of SCD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eprevious ICD insertion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICD implant types (N)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSingle chamber ICD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDual-chamber ICD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiventricular\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e demonstrates our patients' mortality and side effects of ICD implantation. Most of our study population had no side effects. But the main complications were unexplained syncope and lead-related problems, including disconnected leads, wire displacements, and lead breakage. Two of our patients died of decompensated heart failure, one from stroke and one from myocardial infarction.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMortality and side effects of ICD implantation in the study population*\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAppropriate shock (n\u0026thinsp;=\u0026thinsp;24)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eInappropriate shock or not receiving a shock (n\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTotal (n\u0026thinsp;=\u0026thinsp;71)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWithout side effects\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e56\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLead related complications\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElectric shock and shock mode\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCVA and Left side hemiplegia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnexplained syncope\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeath\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003e*some patients had experienced more than one complication, so the sum of each column exceeds the group size.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWe conducted a Pearson correlation test between receiving an appropriate shock and variables like septal thickness, EF, syncope, family history of SCD, and previous myectomy. The only factor that showed a significant correlation with receiving an appropriate shock was septal thickness among the evaluated variables. (P value\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePearson correlations between appropriate shock and evaluated variables\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAppropriate shock\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSeptal thickness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.93\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnexplained Syncope\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0111\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.37\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMyectomy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.07\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePositive family history of SCD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.71\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWe plotted a ROC curve to find the most sensitive and specific cutoff value for the septal thickness that correlates with an appropriate shock. Our analysis showed that septal thickness of greater than 18 mm had the most desirable sensitivity (87.5%) and specificity (86%) (P-value\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The area under curve is 0.895 (95% Confidence interval 0.796 to 0.957), which shows excellent accuracy of this cutoff point. (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this retrospective study, we analyzed the correlation between receiving an appropriate ICD shock and variables reported to predict SCD, such as EF, family history of sudden death, LV wall thickness, and recent unexplained syncope (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). Of these evaluated variables, only septal thickness showed statistical significance. We then defined the cutoff value of \u0026gt;\u0026thinsp;18 mm for the septal thickness with optimal sensitivity and specificity in predicting appropriate ICD interventions. We also observed that the patients who received an appropriate shock were significantly younger than those who did not at the time of ICD implantation.\u003c/p\u003e \u003cp\u003eICD implantation is the only effective treatment that can prevent SCD in HCM patients (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Still, there are controversies regarding its indications, efficacy, and possible downsides like device complications and inappropriate shocks (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). In our study, 24 out of 71 received an appropriate shock over 15 years (2.25%/y). This data aligns with the most recent studies that report appropriate ICD shock occurrence to be 2.3%/y \u0026ndash; 4.9%/y (\u003cspan additionalcitationids=\"CR21 CR22\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). A meta-analysis conducted in 2012 reported an appropriate shock rate of 3.3%/year and a low mortality rate following ICD implantation (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). Also, Maron et al. suggest that ICD interventions, especially in primary prevention, are highly effective, and patients with only one risk factor should be considered for ICD implantation (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). However, inappropriate shocks might happen in about 20% of patients, and every inappropriate shock can increase mortality (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e). Also, ICD complications are not negligible (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e). Further research is needed to find more accurate predictors of appropriate shocks (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this study, we found no correlation between appropriate shocks and risk factors like EF, family history of SCD, and recent unexplained syncope. Still, our data demonstrated an association between appropriate ICD intervention and septal thickness. Previous studies report a low predictive utility of the conventional risk factors for appropriate shocks (i.e., age, EF, severe LVH, NSVT, atrial fibrillation, recent unexplained syncope, and family history of SCD) (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). The significance level for the correlation of appropriate shocks and conventional risk factors is estimated to be 15% (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). Despite these risk factors' low positive predictive accuracy, they have remarkable negative predictive accuracy (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e). More recent data demonstrate that severe late gadolinium enhancement in MRI before ICD implantation, left atrial volume index (LAVI), and global longitudinal strain could predict appropriate ICD shocks more accurately than other risk factors (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMaron et al. showed that the risk of SCD had a direct correlation with wall thickness as the cumulative risk of death in 20 year period for thickness\u0026thinsp;\u0026lt;\u0026thinsp;20mm is negligible, but approximately 40% for wall thickness\u0026thinsp;\u0026ge;\u0026thinsp;30 mm. the magnitude of hypertrophy directly and independently predicts HCM prognosis (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e). The latest ACC/AHA guideline suggests that LV wall thickness\u0026thinsp;\u0026ge;\u0026thinsp;30 mm should be considered an isolated risk factor (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e); on the other hand, Olivetti et al. stated the exact opposite. Their result showed no correlation between the extent of LV hypertrophy and cardiovascular mortality in HCM patients unless detected at a very young age (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e). Our study demonstrated that septal thickness significantly correlated with receiving an appropriate shock. However, our analysis showed that a septal thickness of \u0026gt;\u0026thinsp;18 mm rather than \u0026ge;\u0026thinsp;30 mm can predict appropriate shocks more accurately. A septal thickness of more than 18mm has 87.5% sensitivity and 86% specificity. The decision-making about ICD implantation must be individualized for each patient and based on their condition. Still, this new cutoff value used in the context of the most recent guidelines, can help physicians to be more selective and accurate.\u003c/p\u003e \u003cp\u003eWe observed that the patients who received appropriate shock were significantly younger than those who did not, with a mean age difference of approximately seven years (41.3\u0026thinsp;\u0026plusmn;\u0026thinsp;13.3 versus 48.4\u0026thinsp;\u0026plusmn;\u0026thinsp;19.1). Previous studies reported that SCD mostly happens in younger patients but is not confined to them (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e). Also, age affects the significance of other risk factors (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Our observation regarding this matter aligns with the theory that SCD mainly occurs in younger patients.\u003c/p\u003e \u003cp\u003eGenerally, about 35\u0026ndash;40% of patients suffer from ICD complications (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e). A meta-analysis evaluating 16 cohort studies reported the annualized rate of complications related to ICDs to be 3.4% (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). About 21% of our patients reported complications after ICD implantation. Unexplained syncope (13%) and Problems related to the defibrillator leads (11%) comprised most of our complications. A 2020 study showed that infection, lead fracture, and lead displacement occurred in 12% of their patients. (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e) The mortality rate in our population was 5.6% (4 out of 71) over 15 years (0.37%/y). The Schinke meta-analysis reported annualized cardiac mortality rate of 0.6% (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). Maron points out that despite heart failure patients, ICD discharges are not associated with a significant increase in mortality and morbidity in HCM patients (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). Aside from expected side effects, studies show that every ICD shock can cause a small degree of myocardial damage which can cause a transient troponin rise. Increased mortality in ICD patients after receiving a shock can result from this myocardial damage or an indicator of an overall worse cardiac condition (\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThis study evaluated HCM patients with ICD over a 15-year interval, which helped us include patients who received ICD shocks long after their operation. This is also the first time that the cutoff value of \u0026gt;\u0026thinsp;18 mm has been introduced for predicting appropriate shocks. This study is limited by its population as we selected them from only two centers in the south of Iran. More research with larger study populations is necessary to evaluate this matter further.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eICD implantation has indeed expanded the life span of HCM patients. The risk stratification of SCD in these patients is constantly evolving and changing for the better. We suggest the consideration of septal thickness\u0026thinsp;\u0026gt;\u0026thinsp;18 mm as a potential predictor for appropriate ICD shocks in SCD risk assessment guidelines. Most HCM patients exposed to SCD are generally younger, and maintaining these patients' quality of life is crucial. Therefore physicians should assess every patient individually and precisely regarding ICD implantation. They should be and keep up with the latest findings to reduce the number of inappropriate shocks to the smallest number possible.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eData availability\u003c/h2\u003e\n\u003cp\u003eThe data of the current study is available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003ch2\u003eContributions\u003c/h2\u003e\n\u003cp\u003eS.D. contributed to the conception, participated in data interpretation and assisted in drafting the manuscript. M.A. analyzed the data and drafted the manuscript. M.H.N. designed the study, supervised the study, and critically revised the manuscript. All authors red and approved the final manuscript.\u003c/p\u003e\n\u003ch2\u003eCorresponding author\u003c/h2\u003e\n\u003cp\u003eCorrespondence to\u0026nbsp;Mohammad Hossein Nikoo.\u003c/p\u003e\n\u003ch2\u003eEthics declaration\u003c/h2\u003e\n\u003cp\u003eThis study was conducted in accordance with the declaration of Helsinki(38), and was approved by the institutional review board and ethics committee of Shiraz university of medical sciences with ethics number of IR.SUMS.MED.REC.1400.555.\u003c/p\u003e\n\u003ch2\u003eInformed consent\u003c/h2\u003e\n\u003cp\u003eInformed consent was obtained from all subjects and/or their legal guardians.\u003c/p\u003e\n\u003ch2\u003eCompeting interests\u003c/h2\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMaron BJ, Olivotto I, Spirito P, Casey SA, Bellone P, Gohman TE, et al. 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BMJ Publishing Group Ltd and British Cardiovascular Society; 2013. p. 1223-4.\u003c/li\u003e\n\u003cli\u003eHolm S. Declaration of Helsinki. International Encyclopedia of Ethics. p. 1-4.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Shiraz University of Medical Sciences","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":"Defibrillators, Implantable, Death, Sudden, Cardiac, Cardiomyopathy, Hypertrophic","lastPublishedDoi":"10.21203/rs.3.rs-5391709/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5391709/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction:\u003c/h2\u003e \u003cp\u003eimplantable cardioverter defibrillators (ICD) can prevent sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) patients. Guidelines assess HCM patients regarding SCD risk to identify ICD candidates. This study aimed to evaluate the correlation between receiving an appropriate shock and SCD\u0026rsquo;s main risk factors in patients with ICD.\u003c/p\u003e\u003ch2\u003eMethod\u003c/h2\u003e \u003cp\u003eAll the HCM patients with ICD implantations during 2006 to 2021 in Alzahra and Shahid Faghihi hospitals in Shiraz, Iran who were \u0026ge;\u0026thinsp;18 were included. Patients with other cardiac or chronic underlying diseases were excluded. Patients were divided into two groups based on receiving an appropriate or inappropriate shock. We used Pearson correlation test to find correlations between receiving an appropriate shock and cardinal risk factors of SCD. A receiver operating characteristic curve was plotted to define a cutoff point for the variables that were correlated to appropriate shock.\u003c/p\u003e\u003ch2\u003eResult\u003c/h2\u003e \u003cp\u003eWe enrolled 71 patients (65% male). The mean age of participants was 46.0\u0026thinsp;\u0026plusmn;\u0026thinsp;17.5 years. Patients who experienced an appropriate shock during the follow-up period (24 patients), were younger (41.3\u0026thinsp;\u0026plusmn;\u0026thinsp;13.3 years). Only septal thickness of \u0026gt;\u0026thinsp;18mm showed a significant correlation with receiving an appropriate shock with 87.5% sensitivity and 86% specificity (all P values\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The mortality rate in our population was 5.6%.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003econventional risk factors of SCD have a low predictive utility for appropriate shocks. The latest guidelines state that left ventricle wall thickness\u0026thinsp;\u0026ge;\u0026thinsp;30 mm is an isolated risk factor. We suggest the septal thickness\u0026thinsp;\u0026gt;\u0026thinsp;18mm as a potential risk factor in SCD risk assessment guidelines.\u003c/p\u003e","manuscriptTitle":"Septal Thickness as a Predictor for Appropriate ICD Shocks in Hypertrophic Cardiomyopathy Patients","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-11-06 11:16:09","doi":"10.21203/rs.3.rs-5391709/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":"bae098cb-c978-40a1-a024-721520a034bf","owner":[],"postedDate":"November 6th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":39821203,"name":"Cardiac \u0026 Cardiovascular Systems"}],"tags":[],"updatedAt":"2024-11-06T11:16:09+00:00","versionOfRecord":[],"versionCreatedAt":"2024-11-06 11:16:09","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5391709","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5391709","identity":"rs-5391709","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}