Late potentials and ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy

We studied 38 patients (mean age 32 +/- 14 years) with arrhythmogenic right ventricular cardiomyopathy (ARVC) to evaluate the clinical significance of histologic features on endomyocardial biopsy specimens as related to signa l-averaged electrocardiography (SAECG), spontaneous ventricular arrhythmias , and hemodynamic features. Fifteen patients presented with ventricular tac hycardia or fibrillation (sustained ventricular arrhythmias), 23 with of he r minor arrhythmias, SAECG variables and right ventricular election fractio n (RVEF) were statistically correlated with the extent of myocardial fibros is on biopsy in ARVC, An increased percentage of fibrous tissue (greater th an or equal to 30%) was a significant univariate predictor of late potentia ls (p = 0.004) and reduced RVEF (p = 0.02). The 18 patients with late poten tials had an increased percentage of fibrous tissue (p = 0.01), a reduced R VEF (p = 0.0004), and a higher risk for sustained ventricular arrhythmias ( p = 0.05) than the 20 patients without late potentials, RVEF was the most p owerful predictor of late potentials (p = 0.004) at multivariate analysis, Moreover, RVEF less than or equal to 50% was associated with an increased r isk for development of sustained ventricular arrhythmias (p = 0.02), A SAEC G parameter, namely the root-mean-square voltage of the terminal 40 ms at 2 5 Hz, was an independent predictive factor for the occurrence of: sustained ventricular arrhythmias (p = 0.02), Although Fibrous tissue may contribute to delayed myocardial activation in ARVC, a reduced RVEF plays an essentia l role for spontaneous manifestation of sustained ventricular arrhythmias, (C) 1999 by Excerpta Medica, Inc.