Angiotensin-converting enzyme (ACE) inhibitors, such as enalapril work to reduce heart failure by allowing blood vessels throughout the body to relax. Robertson, S. (2015) reported that ACE inhibitors achieve their goal, in lowering blood pressure, by competitively inhibiting angiotensin I from converting to angiotensin II, resulting in systemic vasodilation. When arterial pressure becomes decreased, the heart workload decreases. This will reduce both the amount of volume returning to the heart (preload) and the amount of resistance the left ventricle must overcome to pump blood. Since angiotensin II ultimately aids in the release of aldosterone, a hormone causing sodium and water retention, ACE inhibitors would also promote the excretion of sodium and water in the renal tubules.