Morphologic left ventricular patterns and prevalence of high-grade ventricular arrhythmias in the normotensive and hypertensive elderly

In the elderly, systemic hypertension is the main risk factor for cardiovas cular diseases. Left ventricular hypertrophy, the most common adaptation to chronic pressure overload, has been recognized as an independent risk fact or for an increased incidence of sudden death and arrhythmic disturbances. This study compared the prevalence of serious ventricular arrhythmias in el derly individuals with uncomplicated hypertension and in normotensive age-m atched controls, using left ventricular mass index (LVMI) to differentiate patterns of anatomic adaptation to systolic, diastolic, or systolic-diastol ic hypertension. The study enrolled 378 consecutive untreated elderly subje cts (greater than or equal to 65 years of age), without clinical evidence o f heart failure; 203 were hypertensive and 175 were normotensive. Each part icipant underwent standard 12-lead electrocardiography, M-mode and B-mode e chocardiography, and 24-hour ambulatory electrocardiographic monitoring. Se rious, statistically significant arrhythmias (Lown classes greater than or equal to3) were present in 6.8% of normal subjects versus 17.1% of individu als with systolic, 31.5% of those with diastolic, and 20.4% of participants with systolic-diastolic hypertension. Arrhythmias did not differ in terms of left ventricular morphologic patterns or LVMI or between subgroups of hy pertensive patients. Our data support the hypothesis that the pathogenesis of arrhythmias is related not to the electrophysiologic derangement of hype rtrophied muscle but, rather, to the effects of hypertension on the cardiac structure. Cardiac fibrosis, one of the deleterious events accompanying hy pertension, may be the main substrate for ventricular arrhythmias.