Comparison of the new risk prediction model (HCM Risk-SCD) and classic risk factors for sudden death in patients with hypertrophic cardiomyopathy and defibrillator

AIMS: Hypertrophic cardiomyopathy is one of the main causes of sudden death in young people. Recent clinical practice guidelines include a risk prediction model for sudden death (HCM Risk-SCD), which facilitates the decision of whether to implant a defibrillator. The aim of our study was to ascertain the percentage of events in our series of primary prevention implantable cardioverter-defibrillator recipients with hypertrophic cardiomyopathy and whether HCM Risk-SCD predicts the onset of arrhythmic events. METHODS AND RESULTS: This was an observational, retrospective cohort study, which included 48 primary prevention defibrillator recipient patients with HCM. We compiled their demographic and clinical characteristics, estimated 5-year risk using HCM Risk-SCD, and collected the documentation on arrhythmias during follow-up. The majority was male (66.7%) and mean age at implantation was 44.44 ± 14.46 years. Non-sustained ventricular tachycardia was the most prevalent risk factor (66.67%), followed by a family history of sudden death (47.92%). Mean HCM Risk-SCD was 6.15 ± 5.01%. HCM Risk-SCD was the only factor independently associated with the onset of ventricular tachyarrhythmia, above any other classic risk factor or association odds ratio = 1.46 (95% confidence interval 1.051-2.013); P = 0.02. None of the 11 patients estimated as low risk using HCM Risk-SCD suffered any appropriate events (P < 0.05). CONCLUSIONS: During an average follow-up of 4 years, 16.67% presented appropriate events (4.16%/year). HCM Risk-SCD predicted the onset of events more suitably than classic risk factors.