The spectrum of left ventricular size in dilated cardiomyopathy: clinical correlates and prognostic implications. SPIC (Italian Multicenter Cardiomyopathy Study) Group.

To address the issues of variability and prognostic role of left ventricular dimensions in dilated cardiomyopathy (DCM), 144 patients with DCM were studied. They were arbitrarily assigned to two groups according to an echocardiographic left ventricular end-diastolic diameter index < or = 15% (45 patients with mildly dilated cardiomyopathy) and above 15% (99 patients with typically dilated cardiomyopathy) of the upper normality range. Among the patients with mildly dilated cardiomyopathy, there were more men (89% vs 66%; p < 0.01). This group of patients also had a greater prevalence of atrial fibrillation (22% vs 3%; p < 0.001) higher left ventricular fractional shortening (15 +/- 6% vs 13 +/- 5%; p < 0.05), higher ejection fraction (28 +/- 8% vs 24 +/- 8%; p < 0.01), and a lower exercise tolerance (5 +/- 2 MET vs 6 +/- 2 MET; p < 0.05). At the time of follow-up examination (30 +/- 15 months), event-free survival was not significantly different between patients with mildly dilated cardiomyopathy and those with typically dilated cardiomyopathy. Pulmonary capillary wedge pressure (p < 0.001) and left atrial dimension index (p < 0.01) were significant predictors of prognosis as determined by Cox multivariate analysis. Minimal or mild ventricular dilatation is not uncommon in DCM, and it identifies a heterogenous group of patients--some who are in the early stages of disease and others with severe pump dysfunction and persistently small hearts. Ventricular dilatation is not an independent predictor of prognosis.