What pattern of sarcomere addition characterizes eccentric hypertrophy?

What pattern of sarcomere addition characterizes eccentric hypertrophy?

• A. Sarcomeres added in parallel
• B. Sarcomeres added in series making longer sarcomeres
• C. Concentric thickening with reduced chamber size
• D. End-diastolic volume decreases

Answer: (B)

Eccentric hypertrophy arises from volume overload, which causes the ventricle to dilate. To accommodate the increased blood volume, the heart lengthens its muscle fibers by adding sarcomeres in series, producing longer sarcomeres and longer myocytes. This lengthening expands the chamber, elevating end-diastolic volume without proportionally increasing wall thickness. In contrast, adding sarcomeres in parallel thickens the walls and reduces chamber size (concentric hypertrophy) in response to pressure overload. End-diastolic volume tends to rise, not fall, with eccentric remodeling. So the pattern is sarcomeres added in series, making longer sarcomeres.

Eccentric hypertrophy arises from volume overload, which causes the ventricle to dilate. To accommodate the increased blood volume, the heart lengthens its muscle fibers by adding sarcomeres in series, producing longer sarcomeres and longer myocytes. This lengthening expands the chamber, elevating end-diastolic volume without proportionally increasing wall thickness. In contrast, adding sarcomeres in parallel thickens the walls and reduces chamber size (concentric hypertrophy) in response to pressure overload. End-diastolic volume tends to rise, not fall, with eccentric remodeling. So the pattern is sarcomeres added in series, making longer sarcomeres.