Cardiac Medicine Certification (CMC) Practice Exam

What is the primary action of ACE inhibitors in heart failure treatment?

1. Increase heart rate

2. Prevent angiotensin-converting enzyme activity

3. Enhance water retention in kidneys

4. Promote vasodilation through beta receptors

The correct answer is: Prevent angiotensin-converting enzyme activity

The primary action of ACE inhibitors in heart failure treatment is to prevent angiotensin-converting enzyme (ACE) activity. This mechanism is crucial because ACE inhibitors block the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. By inhibiting this conversion, ACE inhibitors effectively reduce the levels of angiotensin II in the body, leading to a decrease in blood pressure and reduced strain on the heart. In heart failure management, this reduction in angiotensin II helps to alleviate symptoms by decreasing vascular resistance and promoting vasodilation, which makes it easier for the heart to pump blood. Additionally, ACE inhibitors decrease the secretion of aldosterone, which helps to reduce fluid retention and the resulting volume overload that can exacerbate heart failure symptoms. Other options highlight mechanisms that do not accurately represent the action of ACE inhibitors. Increasing heart rate is not a primary function of ACE inhibitors; in fact, they may help improve cardiac output without increasing heart rate. Similarly, while ACE inhibitors can influence fluid balance through the renin-angiotensin-aldosterone system, they do not directly enhance water retention in the kidneys; in contrast, they contribute to fluid removal due to decreased aldosterone production. Lastly, they do not promote