Mineralocorticoid receptor (MR) activation has been shown to play a deleterious role in the development of
heart disease in studies using specific MR antagonists (
spironolactone,
eplerenone) in both experimental models and patients. Pharmacological MR blockade attenuates the transition to
heart failure (HF) in models of systolic
left ventricular dysfunction and
myocardial infarction, as well as diastolic dysfunction, in rats and mice. In humans, MR antagonism is highly beneficial in patients with mild or advanced HF and postinfarct HF. The consequences of
aldosterone and MR activation for
cardiac arrhythmia and its prevention and/or correction by MR antagonists are often underestimated. Activation of MR modulates cardiac electrical activity, causing atrial and ventricular arrhythmias. A pro-arrhythmogenic effect of
aldosterone (possibly partly dependent on
fibrosis) has been suggested by several studies. Cardiac MR activation has important consequences for the control of cellular
calcium homeostasis, action potential lengthening, modulation of
calcium transients and sarcoplasmic reticulum diastolic leaks, resulting in the promotion of rhythm disorders.
Aldosterone and/or MR activation (in both cardiomyocytes and coronary vessels) result in vascular dysfunction and also contribute to pro-arrhythmogenic conditions. Together, the pro-arrhythmic effects of
aldosterone and/or MR may explain the highly beneficial effect of MR antagonism, namely a decrease in the incidence of
sudden death, observed in the Randomized
Aldactone Evaluation Study (
RALES) and
Eplerenone Post-Acute
Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS) studies.