Work

Cardiac rhythm in hypertension assessed through 24 hour ambulatory electrocardiographic monitoring. Effects of load manipulation with atenolol, verapamil, and nifedipine.

Year: 1983

Type: article

Abstract: In systemic hypertension left ventricular wall stress (afterload) is reduced and function enhanced, compared with normal, in the presence of concentric hypertrophy; the opposite occurs when hypertrophy is combined with dilatation.In this study we tested the hypothesis that cardiac rhythm may be related, in part, to the interacting variables: left ventricular structure, afterload, and function.Eighty-five primary hypertensives were divided into three groups: group 1 (24 cases with normal sized heart), group 2 (33 cases with concentric hypertrophy), and group 3 (28 cases with hypertro- phy and dilatation).Cardiac rhythm, through 24-hour ambulatory electrocardiographic monitoring, and end-systolic left ventricular circumferential wall stress were investigated before and after seven days of treatment with atenolol, verapamil, and nifedipine in groups 1 and 2, and with the two calcium antagonists in group 3.Atrial and ventricular extrasystoles were recorded in 75 to 100% of the subjects in the control group (13 normotensives) and in the hypertensive groups.Average 24 hour atrial ventricular extrasystoles in group 1, and ventricular extrasystoles in group 2, were similar to normal before treatment and were not affected by drugs; changes in circumferential wall stress with treatment were comparable.In group 2 the number of atrial extrasystoles in 24 hours was significantly higher than in all the other groups.They were not influenced by changes in wall stress, and were interpreted as related to the atrial "booster pump" action in the presence of concentric hypertrophy.In group 3 a great number of ventricular extrasystoles was associated with the highest baseline left ventricular afterload; circumferential wall stress and ventricular extrasystoles were poorly affected by ver- apamil, while the remarkable circumferential wall stress reduction caused by nifedipine was paral- leled by an obvious decrease in ventricular extrasystoles.These data support the possibility that in systemic hypertension a relation exists between cardiac structure, load, and rhythm, and that ventricular arrhythmias may benefit from effective left ven- tricular unloading.Although the pathophysiology of the hypertensiveIn the natural history of high blood pressure the heart and the influence of therapy have been investi-condition of the heart is not static, but is subject to a gted extensively over the years, cardiac rhythm in progression of interrelated anatomical and functional high blood pressure has remained almost entirely neg-changes.'-3Schematically, three successive structural lected.steps may be outlined: normal heart, concentric hypertrophy, and hypertrophy associated with left Accepted for publication

Source: Heart

DOI: 10.1136/hrt.50.2.118