Candesartan and arterial baroreflex sensitivity and sympathetic nerve activity in patients with mild heart failure

The purpose of this study was to investigate the effects of candesartan on arterial baroreflex sensitivity (BRS) and sympathetic activity in patients with mild heart failure (HF). Arterial pressure, heart rate, plasma renin activity, plasma angiotensin II and noradrenaline, and muscle sympathetic nerve activity (MSNA) were measured before therapy and after 4 weeks in 20 patients with mild HE Patients were assigned to a candesartan group (n = 10) or a placebo group (n = 10). Baroreflex sensitivity was assessed by using phenylephrine. Candesartan induced an increase in plasma renin activity and plasma angiotensin II associated with a reduction in arterial pressure without affecting heart rate. Although plasma noradrenaline was unchanged (320 +/- 322 pg/ml to 339 +/- 104 pg/ml), MSNA decreased significantly (52 +/- 11 bursts/min to 42 +/- 9 bursts/min; p < 0.01) and BRS increased significantly (6.9 +/- 3.6 msec/mm Hg to 10.2 +/- 3.3 msec/mm Hg; p < 0.01) after candesartan. However, there were no significant changes in the measured variables in the placebo group. These data indicate that candesartan treatment enhanced BRS and reduced sympathetic activity in patients with mild HE Thus, the inhibitory effect of candesartan on sympathetic activity may, at least in part, contribute to the beneficial effect of angiotensin II receptor blockade in patients with mild HF.