To the Editor,

We would like to thank Dr Méndez Bailón and his colleagues for their comments. In patients with heart failure and left ventricular systolic dysfunction (LVSD), the use of aldosterone antagonists (AA) has been shown to improve survival. The effects of AA are believed to be mediated through neuro-hormonal modulation and not primarily though volume homeostasis. Aldosterone antagonists also improve cardiac remodeling, decreasing ventricular size and improving function.1 In contrast to its proven effects in LVSD, the effects of AA in patients with left heart failure and preserved ventricular ejection fraction2 or in patients with right heart failure have not been as extensively studied.3

Experimental data suggest that AA may improve endothelial function and nitric oxide release.4 A pilot study in Colorado, USA, is currently investigating the role of secondary hyperaldosteronism in patients with right ventricular failure and pulmonary arterial hypertension (World Health Organization Group 1).5

One of the primary endpoints of the study will be to determine the 6-month effects of spironolactone on brain natriuretic peptide levels and hemodynamic parameters. This study will hopefully provide some insights on the role of AA in right heart failure. In patients with transposition of the great vessels and systemic right ventricles, elevation in aldosterone levels has also been noted.6 More generally in congenital heart disease, it has been shown that aldosterone levels are elevated in patients with asymptomatic right ventricular dysfunction, and regardless of the type of malformation.7

At least 2 studies are investigating the effect of eplerenone or spirinolactone in patients with systemic right ventricle (ClinicalTrials.gov identifier: NCT00703352, Spain) or congenital heart diseases (ClinicalTrials.gov identifier: NCT01069510, USA).

These studies will help us establish whether AA improves survival or hospitalization rates in patients with right heart failure.

At this time, a pragmatic approach adding AA to loop diuretics in patients with right heart failure and refractory volume overload appears reasonable. Whether this will be translated into better symptoms or prognosis appears unknown at this time. We have to acknowledge that, even in 2010, right heart failure remains an empirical field.