Predictors of arrhythmic events in hypertrophic cardiomyopathy patients with an implantable cardioverter defibrillator: a systematic review and meta-analysis

AIMS: Hypertrophic cardiomyopathy (HCM) is a common genetic cardiac disorder and a leading cause of sudden cardiac death (SCD). Implantable cardioverter defibrillators (ICDs) are critical for SCD prevention, but risk stratification remains challenging. The aim of this study is to evaluate the predictive performance of conventional risk factors for arrhythmic events in HCM patients with ICDs. METHODS AND RESULTS: We conducted a systematic search of PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Clinical Trials from inception to November 2024, including studies reporting hazard ratios (HRs) for clinical, electrocardiographic, and imaging predictors of arrhythmic events in ICD recipients with HCM. Pooled HRs were calculated using random-effects model. Twelve studies of 3297 HCM patients with ICDs (91% primary prevention and 9% secondary prevention) were included, with a mean age of 50 years. The annual arrhythmic event rate was 5% [95% confidence interval (CI): 4-7%] during a mean follow-up of 4 years. Significant predictors of arrhythmic events included non-sustained ventricular tachycardia (NSVT) (HR: 2.19, 95% CI: 1.62-2.98), left ventricular ejection fraction (LVEF) <50% (HR: 1.91, 95% CI: 1.27-2.89), intraventricular pressure gradient >30 mmHg (HR: 1.92, 95% CI: 1.03-3.56), and secondary prevention indication (HR: 2.18, 95% CI: 1.39-3.41). Sensitivity analysis in the primary prevention subgroup confirmed NSVT and LVEF <50% as consistently significant predictors, while other traditional risk factors showed limited predictive value. CONCLUSION: Specific markers remain strong predictors of arrhythmic events in HCM patients with ICDs, but other traditional risk factors may lack predictive utility.