Effects of angiotensin II (AT1) receptor blockade on cardiac vagal control in heart failure

The objective of the present study was to determine the autonomic effects of angiotensin II (AT 1 ) receptor blocker therapy in heart failure. In a randomized double-blind cross-over study, we compared the effects of candesartan and placebo on baroreflex sensitivity and on heart rate variability at rest, during stress and during 24h monitoring. Acute effects were assessed 4h after oral candesartan (8mg) and chronic effects after 4 weeks of treatment (dose titrated to 16mg daily). The study group comprised 21 patients with heart failure [mean (S.E.M.) ejection fraction 33% (1%)], in the absence of angiotensin-converting enzyme (ACE) inhibitor therapy. We found that acute candesartan was not different from placebo in its effects on blood pressure or mean RR interval. Chronic candesartan significantly reduced blood pressure [placebo, 137 (3)/82 (3)mmHg; candesartan, 121 (4)/75 (2)mmHg; P P