Which of the following statements best describes the action of ACE inhibitors on the failing heart?

ACE inhibitors have a significant role in the management of heart failure, primarily due to their ability to modify hemodynamics and neurohormonal responses in the cardiovascular system.

When considering the action of ACE inhibitors, it's important to understand that they inhibit the angiotensin-converting enzyme, which leads to decreased production of angiotensin II. Angiotensin II is a potent vasoconstrictor and plays a key role in increasing vascular resistance. By blocking this enzyme, ACE inhibitors help to decrease vascular resistance, which in turn helps reduce afterload on the heart.

In terms of preload, ACE inhibitors can decrease it by promoting vasodilation and decreasing blood volume. They do this by reducing the secretion of aldosterone, a hormone that promotes sodium and water retention. This reduction in fluid volume ultimately lowers preload, or the volume of blood that returns to the heart before it contracts.

While it might seem that decreased cardiac output could be a concern in heart failure, the use of ACE inhibitors generally aims to improve symptoms and functional capacity through their beneficial effects on preload and afterload rather than directly increasing cardiac output. Furthermore, ACE inhibitors work to oppose the excessive activation of the renin-angiotensin-aldosterone system (RAAS) that often