USMLE Step 3 - Question 12

A 42 year old male with a history of hypertension has been experiencing dyspnea on exertion. He denies any chest pain. His blood pressure is 140/40, heart rate 90, and  respirations 18. Physical examination reveals elevated jugular venous pressure, an early systolic ejection sound is heard. A III/IV early diastolic decrescendo murmur heard best at the right upper sternal border is present along with a I/IV diastolic rumble at the apex. Also noted is a II/VI systolic ejection murmur at the right upper sternal border. What other physical exam finding might you expect?

A. Pulsus bisferens

B. Pulsus alternans

C. Pulsus paradoxus

D. Pulses parvus et tardus

The patient has severe aortic regurgitation (aka aortic insufficiency) which is characterized by symptoms of congestive heart failure (i.e. dyspnea on exertion, lower extremity edema, generalized fatigue). The murmur of aortic regurgitation is an early diastolic decrescendo murmur. An additional diastolic murmur can sometimes be heard at the apex due to the regurgitant blood striking the anterior leaflet of the mitral valve causing it to vibrate (Austin-Flint murmur). Also, due to the high flow state across the aortic valve, an aortic flow systolic ejection murmur can be heard at the aortic listening post (since a good portion of the blood ejected out of the left ventricle goes backward, a proportionally larger amount must be ejected forward to maintain normal cardiac output). This is the one cardiac condition that can mimic the murmur of a patent ductus arteriosis since they both have audible murmurs in systole and diastole. If the murmur is located at the right upper sternal border, then a dilated aortic root is causing the aortic valve leaflets not to coapt resulting in the regurgitation. If the murmur is heart at the left lower sternal order or Erb's point, then there is an actual problem with the leaflets themselves (i.e. bicuspid or endocarditis). Lastly, the pulse pressure is widened since again there is significant backflow of blood in diastole into the left ventricle which reduces the diastolic pressure. This patient has an extra systolic sound which may be from a bicuspid aortic valve.

Pulses bisferens occurs in patients with significant aortic valve regurgitation. There is a double pulse felt due to the backflow of blood in early diastole. The first carotid pulse felt is normal systole. The second is early diastolic due to the regurgitating blood. Pulses alternans occurs with severe left ventricular failure. Pulses paradoxus occurs in cardiac tamponade or severe asthma exacerbations. Pulsus parvus et tardus is the physical exam finding in aortic valve stenosis. The term "parvus" means weak and "tardus" means late, thus the pulse is weak and late.