4786Discordance between the criteria for ICD implantation in the primary prevention of sudden death among patients with hypertrophic cardiomyopathy

Abstract

Background/Introduction: The European (ESC) and American (ACC) guidelines use different criteria to identify patients with hypertrophic cardiomyopathy (HCM) who may benefit from an implantable cardioverter defibrillator (ICD). Recently, late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) was proposed to improve patient selection. Purpose(s): Our objective was to assess the prevalence and concordance between these criteria for primary prevention with ICD in a population of patients with HCM referenced for CMR. Method(s): A retrospective analysis was conducted in 3 centres where patients with HCM underwent CMR for diagnostic confirmation and/or risk stratification. Eligibility for ICD was determined according to the ESC criteria (HCM Risk-SCD >=4% at 5-years) and the ACC criteria (presence of at least one of the classic risk factors). LGE was defined as a signal intensity >=6 standard-deviations above the average signal intensity of healthy myocardium. A LGE >=15% of total myocardial mass was considered a risk factor for sudden death. Result(s): From the 100 patients analysed (60% male; age 58+/-15 years) 4% had family history of sudden death, 12% non-sustained ventricular tachycardia on 24h-Holter monitoring, 11% had previous unexplained syncope, and 5% had left ventricular maximum thickness >=30 mm. According to the ACC guidelines, it would be reasonable to consider an ICD in 28 of the 100 patients (25 patients with one risk factor and 3 patients with two risk factors). The median HCM Risk-SCD score was 1.72% (IQR 1.29-2.46%); 11 patients would be eligible for ICD implantation (HCM Risk-SCD >=4% at 5 years). The median % of LGE was 1% (IQR 0-4%). Eight patients (8%) showed LGE >=15% of total myocardial mass. The concordance between these criteria is depicted in Figure 1. All patients eligible for ICD by the ESC guidelines (n=11) were also eligible according to the ACC guidelines. Among the 28 patients in whom an ICD could be considered according to the ACC guidelines, only 11 patients would be eligible by the ESC recommendations. From the 8 patients with LGE >=15%, only 5 and 1 patients would be eligible for ICD according to the ACC and ESC guidelines, respectively. Conclusion(s): In this population of patients with HCM undergoing CMR there was a large discrepancy between the 3 studied criteria for ICD implantation. The clinical importance of this topic warrants a prospective multicentre comparison and validation of these criteria.