The electrocardiographic response to exercise in 44 patients with leaflet prolapse

The response to electrocardiographically monitored submaximal exercise stress testing has been studied in 44 patients with mitral leaflet prolapse (MLP). With exercise, ventricular premature contractions occurred in 7, ventricular tachycardia in 1, and atrial fibrillation in 1. Exercise was terminated short of target heart rate in 18 patients, because of chest pain (5), fatigue (7), ventricular arrhythmia (4), dizziness (1) or ST segment depression (1). 23 patients developed postexercise ST segment abnormalities, of whom 5 had 'ischemic' patterns and arteriographically proven coronary artery disease (CAD); among the 18 others, the ST segments were depressed and minimally downsloping in 2, slowly ascending from depressed J point in 3, horizontal for greater than or equal to 80 msec with J depression of less than 1 mm in 12, and cupped in 1. The incidence of arrhythmias provoked by submaximal exercise stress testing in patients with MLP was lower than suggested in previous reports. In all 5 cases where MLP and CAD coexisted, the classical 'ischemic' electrocardiographic response to exercise was not obscured. Even in the absence of CAD, postexercise ST segment abnormalities were common with MLP (18/39 = 46%) and differed from the progressively resolving ST segment deviation characteristic of CAD with angina. Exercise testing can safely be recommended, subject to standard contraindications, in patients with MLP and yields useful information.