Ventricular arrhythmias in patients with hypertrophic cardiomyopathy: Prevalence, distribution, predictors, and outcome

BACKGROUND Hypertrophic cardiomyopathy (HCM) carries an increased risk of sudden cardiac death. Ventricular fibrillation (VF) is thought to be the common culprit arrhythmia.OBJECTIVE The purpose of this study was to describe the incidence and predictors of sustained ventricular arrhythmias (VTAs) in HCM patients.METHODS We retrospectively analyzed all patients with HCM and an implantable cardioverter-defibrillator (ICD) from a prospectively derived registry in 2 tertiary medical centers. Clinical, electrocardio-graphic, echocardiographic, ICD interrogation, and genetic data were collected and compared, first between patients with and without VTAs and then between patients with only VF and those with ventricular tachycardia (VT) with or without VF.RESULTS Of the 1328 HCM patients, 207 (145 [70%] male; mean age 33 +/- 16 years) were implanted with ICDs. Over a mean follow-up of 10 +/- 6 years, 37 patients with ICDs (18%) developed sustained VTAs. These were associated with a family history of sud- den cardiac death and a personal history of VTAs (P = .036 and P = .001, respectively). Sustained monomorphic VT was the most com-mon arrhythmia (n = 26,70%) and was linked to decreased left ven-tricular (LV) ejection fraction and increased LV end-systolic and end-diastolic diameters. Antitachycardia pacing (ATP) successfully terminated 258 (79%) of the 326 VT events. Mortality rates were comparable between patients with and without VTAs (4 [11%] vs 29 [17%]; P = .42) and between those with and without ICDs (24 [16%] vs 85 [20%]; P = .367).CONCLUSION VT rather than VF is the most common arrhythmia in patients with HCM; it is amenable to ATP and is associated with lower LV ejection fraction and higher LV diameters. Therefore, ATP-capable devices may be considered in HCM patients with these LV features.