The association of ventricular arrhythmias and myocardial dysfunction could be considered an early step toward cardiomyopathy; therefore, we studied 28 patients in NYHA class I and II, characterized by complex ventricular arrhythmias (VA) on 24-h Holter monitoring and volumetric and/or contractile abnormalities on a standard two-dimensional echocardiogram (2-D echo). All patients underwent radioisotopic angiography, 20 patients complete hemodynamic study, and 15 patients endomyocardial biopsy. Ambulatory ECG monitoring showed the presence of frequent premature ventricular contractions in 14 patients (50%) and episodes of ventricular tachycardia in 16 patients (57%). 2-D echo showed mono- or biventricular enlargement and dyssynergies in 25 patients (89%) (left ventricle in 6, right ventricle in 11, both in 8). Two patients showed only left ventricle enlargement and one patient isolated left ventricular dyssynergies. Radioisotopic angiography showed mono- or biventricular ejection fraction reduction in 24 patients (85%) and regional dyssynergies in 24 patients (85%) in accordance with 2-D echo. Hemodynamic study showed in all patients normal coronary arteries, and right and left angiography confirmed enlargement and/or regional dyssynergies. Endomyocardial biopsy was abnormal in 11 of 15 patients: various degrees of hypertrophy, parcellar fibrosis, and adipogenic infiltration were found. Our preliminary data suggest that the simultaneous occurrence of ventricular arrhythmias and ventricular dyssynergies and/or enlargement in patients without apparent clinical heart disease may represent an early stage of dilated cardiomyopathy.