From the Guidelines
Aortic regurgitation is characterized by a high-pitched, blowing, decrescendo diastolic murmur. This type of murmur is described in the 2008 guidelines for the management of patients with valvular heart disease, which states that high-pitched murmurs of aortic regurgitation (AR) are generally decrescendo, consistent with the rapid decline in volume or rate of regurgitation during diastole 1. The murmur begins with or shortly after the second heart sound (S2), when the associated ventricular pressure drops sufficiently below that in the aorta.
Some key characteristics of this murmur include:
- High-pitched and blowing
- Decrescendo, meaning it gradually diminishes in intensity throughout diastole
- Best heard at the left sternal border when the patient leans forward and holds their breath after expiration
- Begins immediately after S2
The severity of aortic regurgitation correlates with the duration rather than the intensity of the murmur, with longer murmurs indicating more significant regurgitation. In acute aortic regurgitation, the murmur may be short and difficult to hear due to rapid equilibration of aortic and ventricular pressures. Associated findings may include a widened pulse pressure, water-hammer (Corrigan's) pulse, and an Austin Flint murmur. The murmur occurs because blood flows backward from the aorta into the left ventricle during diastole through an incompetent aortic valve, creating turbulent flow that produces the characteristic sound.
From the Research
Type of Murmur in Aortic Regurgitation
- The type of murmur associated with aortic regurgitation is typically a diastolic murmur, which occurs when blood flows backward from the aorta into the left ventricle during diastole 2, 3.
- This murmur is often described as a low-pitched, rumbling sound that is best heard at the left sternal border or at the apex of the heart 3.
- The presence and characteristics of the murmur can vary depending on the severity of the aortic regurgitation and the presence of other cardiac conditions 4, 5.
- In some cases, aortic regurgitation may also be associated with a systolic murmur, which can occur when there is concomitant aortic stenosis or other cardiac abnormalities 6.