Disorders of coronary microcirculation and arrhythmias in systemic arterial hypertension

Arterial hypertension is associated with an increased cardiovascular mortality and an increased risk of sudden cardiac death. Therefore, the prevalence of ventricular arrhythmias, identified on 24-hour ambulatory electrocardiographic monitoring, was analyzed in 54 patients (aged 56 +/- 10 years) with arterial hypertension and normal coronary angiograms with respect to left ventricular muscle mass, mass-to-volume ratio, systolic wall stress and coronary microangiopathy. Ventricular ectopic beats (VEBs) were assessed according to a score (modified Lown classification: 1 = no VEB, 2 = less than 30 VEB/hour, 3 = greater than 30 VEB/hour, 4 = polymorphic VEB, 5 = bigeminys, 6 = couplets, 7 = nonsustained ventricular tachycardia). Coronary blood flow was measured by the gas chromatographic argon method. Coronary reserve was determined by measuring coronary resistance before (Rcor) and after (Rmin) administration of intravenous dipyridamole (0.5 mg/kg body weight) (Cor Res = Rcor/Rmin). The frequency (p less than 0.05) and severity (p less than 0.025) of VEBs was higher in normotensive than in hypertensive patients. Although the score of VEBs did not correlate with left ventricular muscle mass (r = 0.20, difference not significant), a slight correlation with mass-to-volume ratio (r = 0.32; p less than 0.05) and systolic wall stress (r = 0.30; p less than 0.05) was found. Hypertensives with a severely reduced Cor Res (less than 2.0) had a significantly higher score of VEBs than those with a nearly normal Cor Res (greater than 3.0) (5.0 +/- 1.5 vs 3.5 +/- 1.7; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)