Acute Aldosterone Antagonism Improves Cardiac Vagal Control in Humans

Abstract Objectives We have examined the acute effects ( Background Evidence for the beneficial effects of aldosterone antagonists comes from studies showing increased survival rates following their addition to standard heart failure therapy. Many mechanisms have been suggested for this action, including effects upon the autonomic nervous system. Methods Heart rate variability and baroreflex sensitivity were examined 30 min following the administration of potassium canrenoate (intravenous) (aldosterone antagonist) or saline (control). Results Active treatment reduced resting heart rate (−6 ± 1 beats/min [mean ± standard error mean]) compared to control (0 ± 1 beat/min) (p 2 with aldosterone antagonism compared to −255 ± 431 ms 2 following saline infusion (p Conclusions These results provide evidence that aldosterone antagonists acutely improve cardiac vagal control, irrespective of any diuretic effects, and may in part explain their beneficial effects in treatment of heart failure.