ARRHYTHMIC PROFILE, VENTRICULAR-FUNCTION, AND HISTOMORPHOMETRIC FINDINGS IN PATIENTS WITH IDIOPATHIC VENTRICULAR-TACHYCARDIA AND MITRAL-VALVE PROLAPSE - CLINICAL AND PROGNOSTIC EVALUATION

Background. In patients with ventricular tachycardia (VT) and apparent ly normal hearts, mitral valve prolapse (MVP) is discovered fairly oft en, raising the question of whether or not it is an occasional finding . Hypothesis: This issue was analyzed in a series of patients with VT and apparently normal hearts in order to define the prevalence of MVP in this condition, the existence of specific diagnostic features sugge sting a nonrandom association between idiopathic VT and MVP, and the p rognostic implications of this finding. Methods. We studied 28 consecu tive patients with documented VT and no history of heart disease. Two- dimensional (2-D) echocardiogram, cardiac catheterization, morphometri c examination of endomyocardial biopsy and arrhythmologic evaluation ( 24-h Holter monitoring, electrophysiologic study, and signal-averaged electrocardiogram) were pet-formed. Inclusion criteria for all patient s were angiographically normal coronary arteries, normal biventricular function, and absence of histologic evidence of myocarditis. Data obt ained in patients found to have MVP at 2-D echo were compared with tho se of the remaining patients. Long-term follow-up data were also colle cted. Results: The prevalence of MVP in our study group was 25% (7 pat ients). It was not associated with leaflet dysplasia or significant re gurgitation. Biventricular function (ventricular volumes and ejection fraction) was comparable in patients with and without MVP. Patients wi th MVP had a significantly higher prevalence of ventricular late poten tials at signal averaged electrocardiogram (86 vs. 29%, p = 0.027), mo re interstitial fibrosis at morphometry (8.5 +/- 3.7 vs. 5.4 +/- 2.7% p = 0.028), and VT of right bundle-branch block morphology (100 vs. 48 %; p = 0.044). Other arrhythmologic findings were similar in the two g roups. After a mean follow-up of >5 years, no patient in either group died, and none developed heart failure or severe mitral regurgitation. Conclusions: Mitral valve prolapse is frequently detected in idiopath ic VT. The distinguishing features of this association are (1) VT of r ight bundle-branch block morphology, (2) high prevalence of ventricula r late potentials, and (3) increased fibrosis on endomyocardial biopsy . Ventricular function and other arrhythmologic findings are not speci fic of this association. Prognosis remains substantially benign, as is true for most cases of idiopathic VT.