Peripheral and facial cyanosis may occur in patients with extremely severe mitral stenosis (MS). In advanced cases there is a malar flush and the facies appear pinched and blue. The jugular venous pulse reveals prominent ‘’a’’ waves due to vigorous right atrial systole in patients with sinus rhythm who have severe pulmonary hypertension or associated tricuspid stenosis. When atrial fibrillation is present, the jugular pulse reveals only a single expansion during systole (c-v wave). The systemic arterial pressure is usually normal or slightly low.
A right ventricular tap along the left sternal border signifies an enlarged right ventricle. The first heart sound may be palpable in patients with pliable valve leaflets. In patients with pulmonary hypertension, the impact of pulmonary value closure can usually be felt in the second and third left intercostals spaces just left of the sternum; the left ventricle is not palpable in severe, pure mitral stenosis.
The first heart sound (S1) is generally accentuated and snapping, and since the mitral valve does not close until the left ventricular pressure reaches the level of the elevated left atrial pressure, this sound is often slightly delayed on phonocardiography, causing a prolonged Q-S1 interval, particularly in patients with severe stenosis. The opening snap (OS) of the mitral valve is most readily audible in expiration at, or just medial to, the cardiac apex but also may be easily heard along the left sterna edge or at the base of the heart. The OS usually ushers in a low-pitched, rumbling, diastolic murmur, heard best at the apex with the patient in the left lateral recumbent position.
Electrocardiogram. In MS and sinus rhythm, the P wave usually suggests left atrial enlargement. It may become tall and peaked in lead II and upright in lead V1. The QRS complex may be normal, even in patients with critical MS. When left ventricular hypertrophy is present in patients with MS, it generally indicates that an additional lesion which places a significant burden on the left ventricle, such as mitral regurgitation, aortic valve disease, or hypertension is present.
Echocardiogram. The echocardiogram is the most sensitive and specific noninvasive method for diagnosing MS. Two-dimensional color Doppler flow echocardiographic imaging and Doppler echocardiography provide critical information, including an estimate of the transvalvular gradient and of mitral orifice size, the presence and severity of accompanying mitral regurgitation, the extent of restriction of valve leaflets, their thickness, and the degree of distortion of subvalvular apparatus. In addition, echocardiography provides an assessment of the size of the cardiac chambers, an estimation of the pulmonary artery pressure, and an indication of the presence and severity of associated tricuspid and pulmonic regurgitation.
Roentgenogram. In severe MS, all chambers and vessels upstream to the narrowed valve are prominent, including the two atria, the pulmonary arteries and veins, right ventricle and superior vena cava. Kerley B lines are fine, dense, opaque, horizontal lines which are most prominent in the lower and midlung fields and which result from distention of interlobular septa and lymphatics with edema when resting mean left atrial pressure exceeds approximately 20mmHg.
Differential diagnosis. Significant mitral regurgitation may be associated with a prominent diastolic murmur at apex, but this murmur commences slightly later than in patients with MS. Primary pulmonary hypertension results in a number of the clinical and laboratory features observed in MS. Left atrial myxoma may obstruct left atrial emptying, causing dyspnea, a diastolic murmur, and hemodynamic changes.