Progressive Care Nursing Certification (PCCN) Practice Exam

Which statement accurately describes the role of the renin-angiotensin system in heart failure?

1. Decreases heart contractility

2. Facilitates the release of glycogen

3. Increases preload and afterload

4. Promotes muscle regeneration

The correct answer is: Increases preload and afterload

The renin-angiotensin system (RAS) plays a crucial role in regulating blood pressure and fluid balance, which significantly impacts heart failure. In heart failure, the body often attempts to compensate for inadequate cardiac output by activating the RAS. This leads to several physiological changes. The correct answer indicates that the renin-angiotensin system increases both preload and afterload. Preload refers to the volume of blood in the ventricles at the end of diastole, while afterload is the resistance the heart must overcome to eject blood during systole. When the RAS is activated, it promotes vasoconstriction, primarily through angiotensin II, which can increase afterload. Additionally, the retention of sodium and water via aldosterone results from RAS activation, which increases blood volume and, consequently, preload. This effect is significant in heart failure, where maintaining cardiac output is critical. While increasing preload can initially support cardiac function by enhancing stroke volume, the increased afterload can eventually hinder the heart's ability to pump effectively, potentially leading to worsening heart failure. The other options do not accurately reflect the role of the RAS in this context. For instance, the decrease in heart contractility is more associated with the pathology of