SUPPRESSING SYMPATHETIC ACTIVATION WITH CLONIDINE ON VENTRICULAR ARRHYTHMIAS IN CONGESTIVE-HEART-FAILURE

This randomized, double-blind, placebo-controlled study examines the e ffects of clonidine (a centrally acting sympathoinhibitor) on ventricu lar arrhythmias in 35 patients with congestive heart failure (CHF) by using the 24-h ambulatory electrocardiographic recording. After baseli ne examination and Holter recording, patients were balanced and 18 pat ients were randomized to clonidine group and 17 patients to placebo gr oup. After four weeks of clonidine (given as a transdermal patch) or m atching placebo therapy, a second Holter recording was obtained. The p lacebo group showed no change in the frequency of ventricular arrhythm ias whereas the clonidine-treated group showed a significant decrease in the frequency of ventricular premature beats by 68% (P<0.01), coupl ets by 63% (P<0.01) and episodes of non-sustained ventricular tachycar dia by 60% (P<0.05). Clonidine also decreased heart rate and arterial blood pressure, but left ventricular ejection fraction was slightly im proved. It is concluded that sympathetic suppression with clonidine re duces the frequency of ventricular arrhythmias in patients with CHF, w hich suggests that sympathetic activation plays a role in arrhythmogen esis in these patients. (C) 1998 Elsevier Science Ireland Ltd.