USMLE cardiology review question murmurs

Question

Dynamic auscultation of suspected Hypertropic cardiomyopathy is important and a favorite USMLE question. 

Which of following is true of murmur?

A. Decreased with hand grip and inspiration

B.  Increased with Valsalva, amyl nitrate, and stand to squat 

C. Increased on beat following PVC

D. Decreased with sympathetic activation

Answer 1

Dynamic auscultation on USMLE usually re: HCM.

*Valsalva- Increased intrathoracic pressure/less blood return/decreased preload/volume- increase murmur

*Stand to squat- forces blood in legs in the heart. Increase volume decreased murmur

*Squat to stand- Opposite above increased murmur

*handgrip- increases heart rate and blood pressure – decreased murmur

amyl nitrate- dilate smooth muscles reduces BP increases murmur

* beat following PVC – increased contractility increases murmur

Sympathetic activation – increases contractility/heart rate increases murmur