Determinants of ventricular arrhythmias in cardiac hypertrophy.

Ventricular arrhythmias occur with increased frequency in both experimental and human cardiac hypertrophy. Although the process of hypertrophy itself may be arrhythmogenic, other factors may contribute to the high prevalence of arrhythmias in hypertensive patients with left ventricular hypertrophy (LVH). Disease of the large epicardial coronary arteries or of the small intramyocardial vessels (coronary microangiopathy) may lead to myocardial ischemia and thus predispose to arrhythmia. Myocardial fibrosis, a common sequelae of cardiac hypertrophy, has also been shown to be associated with ventricular arrhythmias in experimental models. Other possible determinants of ventricular arrhythmias in this group of patients include metabolic abnormalities; studies relating to the importance of hypokalemia in particular have yielded conflicting results. Thus a number of factors may combine to explain the high prevalence of ventricular arrhythmias in hypertensive patients with LVH.