Aortic Stenosis - Physical Exam
Auscultation of the heart in patients with aortic stenosis can be very helpful in both the diagnosis and determining the severity of disease.
The typical murmur of aortic stenosis is a high-pitched, "diamond shaped" crescendo-decrescendo, midsystolic ejection murmur heard best at the right upper sternal border radiating to the neck and carotid arteries (see figure below). In mild aortic stenosis, the murmur peaks in early systole. However, as the disease progresses the peak moves to later in systole since longer time is required to complete LV systole and aortic valve closure is delayed. The intensity of the murmur typically increases as disease progresses; however, when heart failure develops and cardiac output declines, the murmur becomes softer. Thus, the intensity of the murmur is not a good indicator of disease severity.
Auscultation at the cardiac apex may reveal a murmur that may sound midsystolic or holosystolic and may mimic the murmur of mitral regurgitation. However, this is commonly the result of radiation of the murmur of aortic stenosis to the apex rather than coexistent mitral regurgitation. This finding is referred to as "Gallavardin dissociation." To determine if the apical murmur is indeed due to mitral regurgitation or radiation of the murmur of aortic stenosis, dynamic auscultation can be undertaken (see section on dynamic auscultation). At times, the murmur of hypertrophic cardiomyopathy can also mimic the murmur of aortic stenosis. The Valsalva maneuver decreases the murmur of aortic stenosis while it increases the murmur of hypertrophic cardiomyopathy.
The S2 heart sound is often paradoxically split in patients with aortic stenosis due to the significantly delayed closure of the aortic valve, a result of the increased time needed to complete LV systole.
As disease progresses and the aortic valve leaflets lose their mobility, the intensity of S2 decreases. When the S2 sound is no longer audible, it can be concluded that the aortic stenosis is relatively severe. An S4 heart sound is also often present due to the severe concentric left ventricular hypertrophy that develops in aortic stenosis. If an S3 heart sound is present, then significant systolic dysfunction has developed, which is common in end-stage aortic stenosis.
Perhaps the best bedside method to estimate the severity of aortic stenosis is derived from evaluation of the carotid arteries. The phenomenon known as "pulsus parvus et tardus" refers to a weak (parvus) and delayed (tardus) carotid upstroke. To asses for "parvus," it is often helpful to palpate one’s own carotid artery while concurrently palpating the patient's carotid artery. It is important to note that in some elderly individuals the carotids may be stiff due to calcification, which may falsely normalize the carotid upstroke. To assess for "tardus," auscultate the patient's S2 heart sound while palpating their carotid upstroke. The S2 and carotid upstroke should occur almost simultaneously. If the carotid upstroke comes significantly after the S2 heart sound, "tardus" is present indicating severe aortic stenosis. Other physical exam findings in patients with aortic stenosis include those of both right and left heart failure.