Impaired repolarization parameters may predict fatal ventricular arrhythmias in patients with hypertrophic cardiomyopathy (from the CILICIA Registry).

Background: Hypertrophic cardiomyopathy (HCM) is significantly associated with high risk of fatal ventricular arrhythmias (VAs). Increased frontal QRST angle (fQRSTa), Tpe interval, and Tp-e/QTc ratio are described as ventricular repolarization parameters which are related to arrhythmias. In this study, we aimed to investigate the predictive value of these repolarization parameters for fatal VAs in patients with HCM.

Methods: A total of 127 HCM patients (mean age: 47.9 ± 12.6 years; male:79) were enrolled in this retrospective study. All patients underwent transthoracic echocardiography. Moreover, the last electrocardiograms within 3 months prior to the fatal VA documentation were assessed. The primary outcome was the occurrence of fatal VAs including sustained ventricular tachycardia and ventricular fibrillation which were documented from implantable cardioverter defibrillator records.

Results: There were documented fatal VAs in 37 (29.1%) patients during a mean follow-up time of 70.1 ± 22.6 months. The prevalence of fatal VAs was significantly higher in patients with fQRSTa ≥140 degrees (67.4 vs. 7.4%; p < 0.001) and in patients with Tp-e/QTc ratio ≥ 0.19 (61.5 vs. 6.7%; p < 0.001) as compared to others. High Tp-e/QTc ratio (hazard ratio: 1.564; 95% confidence interval: 1.086-4.796; p = 0.032) and high fQRSTa (hazard ratio: 1.864; 95% confidence interval: 1.106-8.745; p = 0.002) were found to be independent predictors of fatal VAs in HCM patients.

Conclusions: Wider fQRSTa, prolonged Tp-e interval, and increased Tp-e/QTc ratio may be associated with fatal VAs in HCM patients. In addition to traditional risk factors, these simple ECG parameters may provide valuable information during evaluation of sudden cardiac death risk in HCM patients.