Outcome and Complications After Implantable Cardioverter Defibrillator Therapy in Hypertrophic Cardiomyopathy

Abstract

P atients with hypertrophic cardiomyopathy (HCM) are at increased risk for sudden cardiac death (SCD), mostly caused by ventricular arrhythmias. SCD may occur as the initial presentation of HCM, often in asymptomatic or mildly symptomatic patients. 1 In fact, HCM is the most frequent cause of SCD in young people, including trained athletes. 2,3 Implantable cardioverter defibrillator (ICD) therapy may effectively terminate potentially life-threatening ventricular arrhythmias, thereby preventing SCD and prolonging life. Still, ICD therapy is not without risk, because inappropriate interventions and device-related complications may occur. Clinical Perspective on p 559Previous observational studies have reported on the use of ICD therapy for primary and secondary preventions of SCD in HCM. A complete overview of outcome and complications after ICD therapy in patients with HCM at risk for SCD is currently not available. The goal of this analysis was to pool the individual studies in an effort to examine the precise rate of cardiac and noncardiac mortality, appropriate and inappropriate interventions, and complications. This knowledge may aid clinical decision making and counseling in patients with HCM at increased risk for SCD considered for ICD therapy. Methods Study DesignThis systematic review and meta-analysis included all available original studies reporting clinical outcome and complications in patients with HCM who underwent ICD implantation. Studies that did not provide data on outcome or complications and review manuscripts were excluded. Studies focussing on SCD in patients with HCM without ICD were excluded. Literature SearchThe online MEDLINE database was searched for literature in Background-Previous observational studies demonstrated that patients with hypertrophic cardiomyopathy at risk for sudden cardiac death (SCD) may benefit from implantable cardioverter defibrillator (ICD) therapy. A complete overview of outcome and complications after ICD therapy is currently not available. This study pools data from published studies on outcome and complications after ICD therapy in patients with hypertrophic cardiomyopathy. Methods and Results-A PubMed database search returned 27 studies on 16 cohorts reporting outcome and complications after ICD therapy in patients with hypertrophic cardiomyopathy. In case of >1 publications on a particular cohort, the publication with the largest number of patients was included in the meta-analysis. ICD interventions, complications, and mortality rates were extracted, pooled, and analyzed. There were 2190 patients (mean age, 42 years; 38% women), most of whom (83%) received an ICD for primary prevention of SCD. Risk factors for SCD were left ventricular wall thickness ≥30 mm (20%), family history of SCD (43%), nonsustained ventricular tachycardia (46%), syncope (41%), and abnormal blood pressure response (25%). During the 3.7-year follow-up, the annualized cardiac mortality rate was 0.6%, the noncardiac mortality rate was 0.4%, and the appropriate ICD intervention rate was 3...

Hypertrophic Cardiomyopathy in Children, Adolescents, and Young Adults Associated With Low Cardiovascular Mortality With Contemporary Management Strategies

“…51 Also, we would expect that this rate of excess ICDs in HCM patients, and SD rates, as well, will decrease further with emerging advances in risk stratification, including use of contrast-enhanced cardiovascular magnetic resonance. 36 Nevertheless, the sizeable proportion of young patients with device complications cited here and elsewhere [1][2][3][4]20,21,[24][25][26][27] contributes to the ICD decision-making dilemma, 52 in which the preservation of life is weighed against the not insignificant potential for inappropriate shocks and lead-related problems over long periods of time. Indeed, the device complication rate of 26% reported here exceeds by 1.7-fold our appropriate ICD intervention rate of 15%.…”

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However, the past 2 decades have witnessed the emergence of an expanded and effective risk stratification model, resulting in more reliable identification of those patients at increased SD risk, who may become candidates for the life-saving benefits of implantable cardioverter-defibrillators (ICDs), 1,9,11,13,[19][20][21][22][23][24][25][26][27] and advancements in heart transplantation, modern resuscitation techniques, and surgical management of outflow tract obstruction, as well. [9][10][11][12][13]23,23,[28][29][30][31] Whether these contemporary management options have resulted in reduced mortality rates for children and young adults with HCM is currently unresolved, and is the subject of the present clinical outcome investigation.

Methods

Patient Selection

Databases from 2 major HCM tertiary referral centers, Minneapolis Heart Institute Foundation and Tufts Medical Center, were accessed and 474 consecutive patients <30 years of age were identified presenting between 1992 and 2013.

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Implantable cardioverter defibrillator therapy in hypertrophic cardiomyopathy: an updated systematic review and meta-analysis of outcomes and complications

“…The incidence of sudden death in HCM is low, around 0.7-1% per annum, and often young patients are affected (2). The use of implantable cardioverter-defibrillator (ICD) protects against SCD secondary to ventricular tachycardia (VT), ventricular fibrillation (VF), or bradycardia, with excellent results (3)(4)(5)(6)(7)(8). A major concern with ICD therapy is the delivery of inappropriate shocks, namely in response to supraventricular tachycardia and atrial fibrillation.…”

“…Prior observational studies have reported on the use of ICD therapy, including a meta-analysis which demonstrated rates of appropriate ICD interventions of 3.3% per year and inappropriate ICD interventions of 4.8% per year (6). However, a number of studies have been published since.…”

Tricuspid regurgitation after implantable cardioverter-defibrillator implantation in patients with arrhythmogenic right ventricular cardiomyopathy

“…Appropriate ICD interventions are believed to terminate arrhythmias, which otherwise might cause sudden cardiac death [10]. We noticed discrepancy in the number of adequate ICD interventions between two groups.…”