RELATION OF COMPLEX VENTRICULAR ARRHYTHMIAS TO PRESENTING FEATURES AND PROGNOSIS IN DILATED CARDIOMYOPATHY

Abstract To evaluate whether complex ventricular arrhythmias relate to presenting features and prognosis of dilated cardiomyopathy, 104 patients were studied from 1977 to 1987. At diagnosis, the 19 patients with complex ventricular arrhythmias (18%), as compared to the 85 patients without (82%), had a higher incidence of palpitation (P less than 0.01), severe dyspnea (P less than 0.001) and atrial fibrillation (P less than 0.01). They showed also higher mean right atrial pressures (10 +/- 5 vs 6 +/- 4 mm Hg, P less than 0.001) and higher right ventricular end-diastolic pressures (11 +/- 4 vs. 7 +/- 4 mm Hg, P less than 0.001) than patients without complex ventricular arrhythmias. Histologic samples were collected from the 32 patients (31%) studied since 1984 and semiquantitatively graded. The 11 patients with complex ventricular arrhythmias showed a higher frequency of severe interstitial fibrosis than the 21 patients without (64% vs. 24%, P less than 0.05), but they were otherwise similar as to the frequency of marked myocellular hypertrophy, changes of myocardial regression, endocardial fibrosis, attenuation of myocytes, hyperplasia of smooth muscle cells and infiltration by inflammatory cells. During a follow-up of 3.8 +/- 3.5 years, 35 patients (34%) died. Mortality was 58% (11 out of 19) in patients with complex ventricular arrhythmias and 28% (24 out of 85) in patients without (P less than 0.025). These results show that complex ventricular arrhythmias in dilated cardiomyopathy are associated with impairment of function of the right heart and severe interstitial fibrosis of the left ventricle, rather than with left ventricular dysfunction. Presence of complex ventricular arrhythmias also seems to identify those at high risk for death.