Mitral Stenosis - Physical Examination

Inspection of the jugular venous pulsations may reveal a prominent A wave due to vigorous atrial contraction of a prominent V wave due to tricuspid regurgitation that develops from pulmonary hypertension. The presence of "mitral facies" refers to a pinkish-purple discoloration of the cheeks produced by a chronic low cardiac output state combined with systemic vasoconstriction. This sign is rare and non-specific.
Palpation may reveal a palpable S1 over the apex. This finding is pathognomonic for mitral stenosis. A diastolic thrill may rarely be appreciated at the apex with the patient in the left lateral decubitus position.

Auscultation of heart sounds will reveal an accentuated S1 early in mitral stenosis and soft S1 in severe mitral stenosis (see Heart Sounds). This occurs since the increased left atrial pressures in early mitral stenosis forces the mobile portion of the mitral valve leaflets far apart. At the onset of ventricular systole, they are forced closed from a relatively far distance resulting in a loud S1. When mitral stenosis becomes more severe and the mitral valve leaflets become significantly more calcified, the mobility of the leaflets decline and they are unable to be separated a great deal, resulting in a soft or even absent S1 heart sound. When pulmonary hypertension develops, the S2 heart sound will be accentuated. A left ventricular S3 is almost always absent in pure MS since LV early diastolic filling is impaired. The significantly increased opening pressures causes an opening snap to occur when the mitral valve leaflets suddenly tense and dome into the LV. This high frequency sound is best heard at the apex.

The murmur of mitral stenosis is low frequency and is referred to as a "rumble". The first part of the murmur of mitral stenosis reflects the pressure gradient between the left atrium and the left ventricle. It begins after S2 with the opening snap and then decrescendos (see picture below) ending in mid diastole. The second part of the murmur occurs just before S1 in a crescendo fashion. This part of the murmur is due to the increased flow of blood through the mitral valve that occurs during atrial contraction. It then makes sense that this aspect of the murmur would be absent if the patient is in atrial fibrillation since active left atrial contraction would be lost.


The severity of mitral stenosis can be estimated on physical exam by the position of the opening snap in diastole and the length of the first part of the murmur. An opening snap that almost immediately follows S2 indicates severe mitral stenosis while an opening snap that occurs later in diastole indicates milder mitral stenosis. This happens since there is a much higher left atrial pressure in severe MS and a transmitral gradient develops immediately after the mitral valve opens. A longer murmur indicates more severe mitral stenosis since it takes more time for both blood to pass through the stenotic mitral valve and for the pressure gradient to dissipate once the mitral valve opens.


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Introduction and Etiology





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