The Syndrome of Systolic Click, Murmur, and Mitral Valve Prolapse-A Cardiomyopathy?

Twenty six patients with systolic clicks, murmurs, and prolapsed mitral valve leaflets were studied because of distressing chest pain or troublesome arrhythmias. Cardiac catheterization revealed normal coronary arteries and a high incidence of left ventricular (LV) dysfunction. The patients, 20 of whom were women, averaged 41 years of age. Thirteen of the 22 patients experienced chest pain of sufficient severity to warrant hospital admission for suspected acute myocardial infarction. Twenty of 26 had abnormal ECG patterns including sinus bradycardia, 1°, 2°, and 3° block, atrial and ventricular arrhythmias and abnormal ST-T wave vectors. Three had patterns of healed transmural infarctions and five of 16 had positive exercise tests. LV dysfunction was hemodynamically documented in 20 patients by either elevated LV end diastolic pressure, low resting cardiac index, or inappropriate rise in cardiac index during exercise. In the remaining six, impaired LV dynamics were demonstrated angiographically. Left ventriculography revealed mitral valve prolapse in all patients, mitral regurgitation in 20, and mild to severe LV hypertrophy in 14 patients. Contractility, determined angiographically, was markedly impaired in 13 patients with marked hypokinesis of the antero-lateral wall of the LV resulting in the appearance of an unusual prominent convexity in this portion of the ventricle in end systole and early diastole. Seven others had similar but less severe impairment of LV contractility. These results indicate that LV dysfunction, possibly related to a primary myocardial disorder, is a significant component of the syndrome of prolapsed mitral valve leaflet. The findings in the symptomatic patients described in this study cannot be generalized to all patients with this syndrome as our sample excluded patients with mild asymptomatic forms of the disease.