What is eccentric hypertrophy?

• A. Enlargement of the left ventricle walls without chamber dilation.
• B. Decrease in heart size due to reduced training.
• C. Pathological dilation with thinning walls.
• D. Overall heart mass increases with enlargement of the chamber and normal wall thickness (left ventricle mostly).

Answer: (D)

Eccentric hypertrophy happens when the heart adapts to volume overload by adding sarcomeres in series, which lengthens the cardiomyocytes and dilates the chamber. This leads to a larger ventricle with normal or only modestly increased wall thickness, and an overall increase in heart mass due to the greater chamber size. The left ventricle is most often affected in this pattern, such as with endurance training or valve regurgitation. So the description of increased heart mass together with chamber enlargement and normally thick walls fits eccentric hypertrophy best. In contrast, concentric hypertrophy features wall thickening with little or no chamber dilation due to pressure overload.