What are the characteristics of the aortic stenosis murmur and its best auscultation location?

From the Guidelines

The aortic stenosis murmur is typically characterized as a loud, late-peaking systolic murmur that radiates to the carotids, and its best auscultation location is at the right second intercostal space.

Characteristics of the Murmur

• The murmur is usually grade 4/6 in severity
• It is a systolic ejection murmur, meaning it occurs during systole and is caused by the ejection of blood from the left ventricle into the aorta
• The murmur radiates to the carotids, which helps to distinguish it from other types of murmurs
• In some cases, particularly in the elderly, the murmur may be soft or radiate to the apex 1

Best Auscultation Location

• The best location to auscultate the aortic stenosis murmur is at the right second intercostal space 1
• This location allows for the best hearing of the murmur as it radiates to the carotids

Associated Physical Examination Findings

• A single or paradoxically split second heart sound (S2) may be present, which can help to confirm the diagnosis of severe aortic stenosis 1
• A delayed and diminished carotid upstroke may also be present, although this finding may be absent in the elderly due to the effects of aging on the vasculature 1

From the Research

Characteristics of the Aortic Stenosis Murmur

• The murmur of aortic stenosis is typically harsh and can be heard at the right base, but may persist with less intensity in elderly patients 2
• The murmur can also be heard as a loud, pure-frequency musical systolic murmur at or near the cardiac apex in some cases 2
• The loudness of the murmur correlates with peak momentum transfer and body size, making it less reliable for predicting severe disease in larger patients 3

Best Auscultation Location

• The murmur of aortic stenosis is typically best heard at the right second intercostal space 4
• The presence of a murmur over the right clavicle can be used to rule out aortic stenosis, while its absence can help rule in the condition 4
• The murmur can also be associated with a carotid bruit, which can be heard in the carotid arteries 5