How do you elicit the murmur of aortic regurgitation?

How to Elicit the Murmur of Aortic Regurgitation

The murmur of aortic regurgitation is best heard by having the patient sit up, lean forward, and hold their breath in full expiration while you listen with the diaphragm of the stethoscope at the left sternal border (3rd and 4th intercostal spaces). 1

Optimal Patient Positioning and Technique

• Position the patient sitting upright and leaning forward to bring the aortic root closer to the anterior chest wall 1
• Have the patient hold their breath in full expiration, as left-sided murmurs like AR are louder during expiration rather than inspiration 2, 1
• Listen with the diaphragm of the stethoscope at the left sternal border (3rd and 4th intercostal spaces), where the high-pitched, decrescendo diastolic murmur is best appreciated 1

Murmur Characteristics to Listen For

• The murmur begins with or shortly after S2, when left ventricular pressure drops below aortic pressure 2, 1
• It is high-pitched and decrescendo in nature, reflecting the gradually decreasing pressure gradient between the aorta and left ventricle during diastole 2, 1
• In severe chronic AR, also listen at the apex for an Austin-Flint murmur (low-pitched, rumbling diastolic murmur), which is a specific finding for severe AR 2, 1

Dynamic Maneuvers to Augment the Murmur

Handgrip Exercise

• Isometric handgrip exercise increases the AR murmur by increasing afterload and systemic vascular resistance 2, 1
• This maneuver is particularly useful when the murmur is faint or equivocal 2

Transient Arterial Occlusion

• Inflate blood pressure cuffs on both arms to 20 mm Hg above peak systolic pressure for 20 seconds 2, 1
• This augments the murmur of AR (as well as mitral regurgitation and ventricular septal defect) but not murmurs from other causes 2

Squatting

• Brisk squatting makes the AR murmur louder by increasing venous return and afterload 2, 1
• Conversely, standing typically diminishes the murmur 2, 1

Amyl Nitrite Inhalation

• During the initial relative hypotension after amyl nitrite inhalation, the AR murmur decreases due to reduced afterload 2, 1
• This can help distinguish the Austin-Flint murmur from true mitral stenosis 2, 1

Important Clinical Pitfalls

• When the diastolic murmur is louder in the right 3rd and 4th intercostal spaces than the left, the AR likely results from aortic root dilatation rather than leaflet deformity alone 2
• A systolic murmur is actually more common than a diastolic murmur in mild to moderate AR detected during routine screening, occurring in 86% of patients with moderate AR and 50% with mild AR 3, 4
• Diastolic murmurs become reliably audible only with moderate to severe AR (present in 100% of moderate and severe cases), while they are rare in mild AR (only 4-13%) 3, 4
• Therefore, do not exclude AR based on the absence of a diastolic murmur alone—a systolic murmur in at-risk patients should prompt further evaluation 3