Late potentials in mitral valve prolapse.
To determine the incidence and significance of late potentials in patients with mitral valve prolapse, we performed surface signal-averaged electrocardiography and 24-hour ambulatory electrocardiographic (ECG) monitoring in 41 patients with moderate to severe mitral valve prolapse on two-dimensional echocardiograms. Late potentials were defined as the presence of either a root mean square voltage of the last 40 msec of the QRS (RMS-40) of less than 20 mu v or a low-amplitude signal duration (LAS-40) of greater than 39 msec. Despite the absence of clinically significant ventricular tachycardia by history and on ambulatory ECG monitoring, 12 patients had late potentials on their signal-averaged electrocardiograms. Clinical characteristics could not differentiate patients with from patients without late potentials, and all patients were doing well at a mean follow-up of 34 months except for one noncardiac death. We conclude that late potentials on the surface signal-averaged electrocardiogram are a common and benign finding in patients with mitral valve prolapse and their clinical significance should be determined only in the presence of other findings.
Jabi
H
H
Department of Medicine, Marshall University School of Medicine, Huntington, WV 25701.
Burger
A J
AJ
Orawiec
B
B
Touchon
R C
RC
D000328:Adult; D003937:Diagnosis, Differential; D004452:Echocardiography; D004562:Electrocardiography / Q000295:instrumentation / Q000379:methods*; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008945:Mitral Valve Prolapse / Q000175:diagnosis* / Q000453:epidemiology; D012189:Retrospective Studies; D013997:Time Factors