A 35-year-old woman with severe aortic stenosis undergoes valve replacement. Histology of the left ventricular myocardium before surgery would most likely show which pattern of adaptation?

• A Increased myocyte number with increased myocyte size
• B Replacement of myocytes by fibrous tissue
• C Decreased myocyte size with decreased myocyte number
• D Increased myocyte size without increased myocyte number ✓

Explanation

Pressure overload (aortic stenosis) causes cardiac myocyte hypertrophy, an increase in cell size without division since adult cardiomyocytes have negligible replicative capacity. Hyperplasia (increased cell number) does not meaningfully occur in the heart. This is a classic Robbins example of pathological hypertrophy. Option A incorrectly adds hyperplasia, which is characteristic of tissues capable of proliferation like the uterus in pregnancy.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.