Arrhythmias and left ventricular asynergy in the prolapsing mitral leaflet syndrome

Abstract

Twenty-four subjects with the prolapsed mitral leaflet syndrome were studied in detail, with emphasis on (1) arrhythmias and the use of exercise testing for their detection and evaluation, and (2) the sequential motions of the left ventricle during the cardiac cycle. Twelve subjects (50 percent) had arrhythmias, usually isolated atrial or ventricular premature beats, on the resting electrocardiogram. With treadmill exercise testing, 16 subjects (75 percent) had arrhythmias. Moreover, in 5 cases exercise testing induced more advanced types of cardiac irritability: bigeminy, trigeminy or transient bouts of atrial and ventricular tachycardia. Arrhythmias tended to diminish during treadmill walking and to reappear in greater profusion immediately after exercise. Left ventriculography showed that 17 subjects (70.8 percent) had asynergistic contractions or relaxations. Sixteen had an anterior convex bulging during late systole or early diastole; 8 of these also had systolic bulging of the inferoposterior wall into the ventricular cavity. One patient had apical akinesia. Selective coronary arteriography, performed in 10 subjects, was noncontributory. The most important clinical problem in patients with prolapsing mitral leaflets is the management of arrhythmias. Deformities of the left ventricular myocardium may be seen during systole and diastole. The relation of this functional myocardiopathy to leaflet prolapse and arrhythmia is obscure.