VENTRICULAR ARRHYTHMIA FACTORS IN MITRAL-VALVE PROLAPSE

To assess the prevalence of ventricular arrhythmias and late potential s (LPs) in mitral valve prolapse (MVP) and to identify clinical, ECG, and echocardiographic markers of spontaneous ventricular arrhythmias, we studied 58 consecutive patients (mean age 46.6 +/- 17.8 years; 29 m ales, 29 females) with MVP diagnosed by echocardiography. Patients und erwent ambulatory ECG recording (n = 58), exercise stress test (n = 56 ), signal-averaged ECG (n = 58), and programmed ventricular stimulatio n (n = 52). Ten patients (17.2%) had spontaneous nonsustained ventricu lar tachycardia (NSVT), 26 patients (44.8%) had premature ventricular contractions (PVCs), Lown grade greater-than-or-equal-to 3 during 24-h our ECG, and 19 had Lown grade greater-than-or-equal-to 3 PVCs during exercise stress test, 13 patients had LPs (22.4%). We provoked sustain ed VT in one case and VSVT in ten cases. Patients with complex ventric ular arrhythmias during 24-hour ECG and exercise stress test were olde r and more often had mitral regurgitation. There was a statistical cor relation between the presence of LPs and spontaneous VT (46.1% vs 8.9% ; P < 0.005) and induced ventricular arrhythmias (50% vs 12.8%; P < 0. 005). No correlation was found between spontaneous ventricular arrhyth mias and thickness or posterior displacement of the mitral valve. In c onclusion, complex ventricular arrhythmia (especially VT) and LPs are frequent in MVP. Patient age and mitral regurgitation seem to be deter minant factors of complex ventricular arrhythmias in MVP. On signal-av eraged ECG, absence of LPs seems to be a good additional marker to ide ntify MVP patients without spontaneous VT. On the other hand, programm ed ventricular stimulation does not appear valuable in determining a M VP subgroup with a high risk of ventricular arrhythmias.