From the Guidelines
Mitral stenosis is typically characterized by a low-pitched, rumbling, diastolic murmur. This murmur is best heard at the apex of the heart with the patient in the left lateral decubitus position 1. The murmur is often described as having a crescendo-decrescendo pattern and is preceded by an opening snap. Key characteristics of this murmur include:
- It begins after the opening snap and continues through diastole
- It becomes louder just before the first heart sound (presystolic accentuation) in patients with sinus rhythm due to atrial contraction
- The intensity of the murmur correlates with the severity of stenosis, with more significant stenosis producing a longer murmur
- The opening snap occurs earlier in severe stenosis due to higher left atrial pressure forcing the stiff mitral valve open sooner 1 Using the bell of the stethoscope with light pressure enhances auscultation of this low-frequency murmur. Maneuvers that increase cardiac output, such as exercise, can accentuate the murmur and make it more audible during clinical examination. In contrast to other murmurs, the murmur of mitral stenosis does not typically decrease with maneuvers like the Valsalva maneuver, which can help distinguish it from other causes of diastolic murmurs 1.
From the Research
Type of Murmur in Mitral Stenosis
- The type of murmur associated with mitral stenosis is a low-pitched, rumbling diastolic murmur best heard at the apex 2, 3, 4.
- This murmur is typically most prominent when the patient is in a left lateral decubitus position and is often accompanied by an opening snap 3, 4.
- The characteristics of the murmur can vary depending on the severity of the mitral stenosis, with more severe stenosis resulting in a louder and longer murmur 4, 5.
- In some cases, patients with mitral stenosis may also have a systolic murmur due to concomitant mitral regurgitation or other cardiac abnormalities 6, 5.
- The presence and characteristics of the murmur can be an important diagnostic clue for mitral stenosis, and can help guide further evaluation and management 2, 3, 4, 6, 5.