Which adaptive mechanisms contribute to heart failure progression in both systolic and diastolic dysfunction?

• A. Increased preload
• B. Neurohumoral activation
• C. RAAS
• D. All of the above

Answer: (D)

In heart failure, the body's attempt to maintain perfusion and pressure ends up fueling progression in both systolic and diastolic dysfunction. Increased preload arises from volume expansion and venous congestion; it can help maintain output at first, but chronic elevation raises wall stress, promotes ventricular dilation, and worsens dysfunction over time.

Neurohumoral activation, particularly sympathetic nervous system stimulation, boosts heart rate and contractility to preserve cardiac output. But prolonged activation leads to maladaptive remodeling, arrhythmias, and further deterioration of function.

RAAS activation adds vasoconstriction and sodium/water retention, which raises preload and afterload while promoting fibrosis and stiffening of the myocardium. This remodeling further impairs both systolic contraction and diastolic relaxation.

Because all of these mechanisms contribute to worsening structure and function, they collectively drive progression in both types of heart failure.