What is pathological hypertrophy?

• A. Enlargement of the heart muscle mass with thicker walls and improved pumping performance.
• B. Enlargement of the heart, especially the left ventricle, with dilation and thinning walls and reduced pumping efficiency.
• C. Enlargement of individual cells without changes in heart size.
• D. A reversible adaptation to endurance training that enlarges cardiac chambers.

Answer: (B)

Pathological hypertrophy is a maladaptive enlargement of the heart driven by disease, often tied to changes in chamber size and wall structure that impair function. This option describes enlargement of the heart, especially the left ventricle, with dilation and thinning of the walls and a decrease in pumping efficiency, which reflects how diseased remodeling can weaken the heart’s ability to eject blood. In other words, the heart enlarges in a way that compromises performance rather than enhances it.

By contrast, responses to regular endurance or strength training typically produce physiological hypertrophy with either thicker walls or increased chamber size that preserves or improves function, not thinning walls or reduced pumping. Enlargement at the cellular level without a change in overall heart size doesn’t capture the organ-level remodeling, and training-related changes are usually reversible adaptations, not pathologic remodeling.