What is the primary mechanism by which pulmonary hypertension leads to right ventricular failure?

• A. Increased afterload and resistance
• B. Decreased oxygenation
• C. Increased preload
• D. Decreased lung volume

Answer: (A)

The primary mechanism by which pulmonary hypertension leads to right ventricular failure is increased afterload and resistance. In pulmonary hypertension, the blood vessels in the lungs become narrowed or obstructed, leading to elevated pressures in the pulmonary arteries. This creates a significant increase in the workload for the right ventricle, which must pump against this higher resistance.

As the right ventricle faces this increased afterload, it has to contract more forcefully to maintain adequate blood flow to the lungs. Over time, this sustained pressure can lead to hypertrophy (thickening of the heart muscle) of the right ventricle, as it adapts to the increased workload. Eventually, the heart may become unable to keep up with the demands, leading to right ventricular failure.

The other mechanisms mentioned do not primarily contribute to the progression of right ventricular failure in the context of pulmonary hypertension. For example, decreased oxygenation may occur as a consequence of pulmonary hypertension but is not the driving force behind right ventricular failure. Increased preload and decreased lung volume also do not adequately describe the underlying pathophysiological changes caused by elevated pulmonary artery pressure that ultimately lead to right ventricular dysfunction. The focus on increased afterload and resistance captures the essential aspect of how pulmonary hypertension creates a strain