Which statement about hypertrophic cardiomyopathy murmurs is true?

Which statement about hypertrophic cardiomyopathy murmurs is true?

• A. They vary with standing or sitting and have a quick carotid upstroke; usually benign
• B. They are diastolic murmurs
• C. They always radiate to the neck
• D. They are best heard at the right upper sternal border

Answer: (A)

Hypertrophic cardiomyopathy murmurs are dynamic systolic murmurs caused by obstruction in the left ventricular outflow tract that changes with preload. Standing or Valsalva lowers venous return and LV volume, making the obstruction worse and the murmur louder; squatting or leg-raising increases preload, reducing the obstruction and softening the murmur. The carotid pulse is often brisk with a rapid upstroke, which helps distinguish this murmur from aortic stenosis, where the pulse rises more slowly. The murmur is best heard along the left lower sternal border and is not a diastolic murmur, nor is it typically heard best at the right upper sternal border or radiating to the neck. So, the statement that it varies with standing or sitting and has a quick carotid upstroke appropriately reflects the key features of hypertrophic cardiomyopathy murmurs.

Hypertrophic cardiomyopathy murmurs are dynamic systolic murmurs caused by obstruction in the left ventricular outflow tract that changes with preload. Standing or Valsalva lowers venous return and LV volume, making the obstruction worse and the murmur louder; squatting or leg-raising increases preload, reducing the obstruction and softening the murmur. The carotid pulse is often brisk with a rapid upstroke, which helps distinguish this murmur from aortic stenosis, where the pulse rises more slowly. The murmur is best heard along the left lower sternal border and is not a diastolic murmur, nor is it typically heard best at the right upper sternal border or radiating to the neck. So, the statement that it varies with standing or sitting and has a quick carotid upstroke appropriately reflects the key features of hypertrophic cardiomyopathy murmurs.