In heart failure, compensatory responses include activation of which systems?

In heart failure, compensatory responses include activation of which systems?

• A. Sympathetic nervous system and renin-angiotensinogen system
• B. Parasympathetic nervous system and renin-angiotensinogen system
• C. Central nervous system and hepatic system
• D. Inflammatory and coagulation pathways

Answer: (A)

When cardiac output falls in heart failure, the body activates two main pathways to maintain blood pressure and perfusion: the sympathetic nervous system and the renin-angiotensin-aldosterone system. Baroreceptors sense the drop in pressure and trigger sympathetic outflow, which increases heart rate and contractility and causes vasoconstriction to raise mean arterial pressure. At the same time, the kidneys respond to reduced renal perfusion by releasing renin, starting the RAAS cascade that produces angiotensin II (a vasoconstrictor) and aldosterone (which promotes sodium and water retention). This preserves stroke volume and preload initially, helping maintain circulation. However, these compensatory responses can become maladaptive over time. The increased afterload from vasoconstriction and the fluid retention from aldosterone expand preload, leading to edema and further strain on the heart. They also contribute to remodeling and worsening heart failure. The other options don’t represent the primary compensatory systems driving early responses to decreased perfusion in heart failure.

When cardiac output falls in heart failure, the body activates two main pathways to maintain blood pressure and perfusion: the sympathetic nervous system and the renin-angiotensin-aldosterone system. Baroreceptors sense the drop in pressure and trigger sympathetic outflow, which increases heart rate and contractility and causes vasoconstriction to raise mean arterial pressure. At the same time, the kidneys respond to reduced renal perfusion by releasing renin, starting the RAAS cascade that produces angiotensin II (a vasoconstrictor) and aldosterone (which promotes sodium and water retention). This preserves stroke volume and preload initially, helping maintain circulation.

However, these compensatory responses can become maladaptive over time. The increased afterload from vasoconstriction and the fluid retention from aldosterone expand preload, leading to edema and further strain on the heart. They also contribute to remodeling and worsening heart failure. The other options don’t represent the primary compensatory systems driving early responses to decreased perfusion in heart failure.