Aortic Regurgitation Auscultation Location
Yes, aortic regurgitation can be heard in the 4th left intercostal space, and when the murmur is louder in this location (along with the 3rd left intercostal space) compared to the right parasternal area, it specifically indicates AR arising from aortic root dilatation rather than primary valve leaflet pathology. 1
Primary Auscultation Sites for AR
The diastolic murmur of aortic regurgitation is typically audible at multiple locations along the left sternal border:
- 3rd and 4th left intercostal spaces are standard auscultation sites where AR murmurs are routinely detected 1
- The murmur is characteristically a decrescendo, high-pitched diastolic murmur that begins immediately after the second heart sound 1
- Best heard with the diaphragm of the stethoscope with the patient sitting up and leaning forward in full expiration 1
Diagnostic Significance of Location
The relative loudness of the AR murmur in different locations provides critical etiologic information:
- When the murmur is louder in the 3rd and 4th left intercostal spaces than in the 3rd and 4th right intercostal spaces, this pattern strongly suggests the AR results from aortic root dilatation rather than isolated valve leaflet deformity 1
- Conversely, when the murmur is louder on the right parasternal border, primary valvular pathology (such as bicuspid aortic valve or rheumatic disease) is more likely 1
Associated Physical Findings
When examining for AR in the 4th left intercostal space, assess for these accompanying signs:
- Displaced left ventricular impulse indicating volume overload 1
- Wide pulse pressure with characteristic peripheral findings (bounding pulses, Corrigan pulse) 1, 2
- Third heart sound (S3) as a manifestation of volume load, not necessarily indicating heart failure 1
- Austin-Flint rumble (low-pitched mid-to-late diastolic murmur at apex), which is a specific finding for severe AR 1
Common Pitfall
Do not dismiss AR based solely on the absence of a murmur in traditional "aortic areas" (2nd right intercostal space). The 3rd and 4th left intercostal spaces are equally valid—and sometimes superior—locations for detecting AR, particularly when aortic root pathology is the underlying cause 1. Always auscultate both the right and left parasternal borders at multiple levels to capture the full spectrum of valvular pathology.