The renin-angiotensin-aldosterone system and heart failure.

The renin-angiotensin-aldosterone system (RAAS) plays a critical role in the pathophysiology of heart failure with reduced ejection fraction (HFrEF). Targeting components of the RAAS has produced significant improvements in morbidity and mortality. Angiotensin-converting enzyme (ACE) inhibitors remain first-line therapy for all patients with a reduced ejection fraction. Angiotensin-receptor blockers may be used instead of ACE inhibitors in patients with intolerance, or in conjunction with ACE inhibitors to further reduce symptoms. Recent data support broader indications for aldosterone antagonists in heart failure, and the combination of an ACE-inhibitor and aldosterone antagonist has become the preferred strategy for dual blockade of the RAAS.