From the Guidelines
Mitral regurgitation is characterized by a high-pitched, blowing, holosystolic murmur, while mitral stenosis produces a low-pitched, rumbling diastolic murmur. The type of murmur in mitral regurgitation and stenosis can be understood by the hemodynamic changes caused by each valvular abnormality. In mitral regurgitation, the murmur occurs when blood flows backward from the left ventricle into the left atrium during systole due to incomplete closure of the mitral valve 1. The intensity of the murmur correlates with the severity of regurgitation.
In contrast, mitral stenosis creates a murmur during diastole when blood flow from the left atrium to the left ventricle is obstructed by a narrowed mitral valve 1. The murmur typically follows an opening snap and may be preceded by a loud S1. The duration of the murmur reflects the severity of stenosis, with longer murmurs indicating more significant narrowing.
Some key points to consider when diagnosing mitral regurgitation and stenosis include:
- The location and radiation of the murmur: Mitral regurgitation is best heard at the apex and radiates to the axilla, while mitral stenosis is best heard at the apex with the patient in the left lateral position using the bell of the stethoscope.
- The timing and duration of the murmur: Mitral regurgitation is a holosystolic murmur, while mitral stenosis is a diastolic murmur.
- The presence of associated sounds: Mitral stenosis is often preceded by a loud S1 and followed by an opening snap.
- The response to maneuvers: The intensity of the murmur can change with different maneuvers, such as respiration, Valsalva maneuver, and exercise 1.
Overall, understanding the characteristics of the murmur in mitral regurgitation and stenosis is crucial for accurate diagnosis and management of these conditions.