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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.

The short- and long-term efficacy of oral encainide was studied in 14 patients with chronic high-frequency ventricular arrhythmias and in 14 patients with chronic frequent episodes of non-sustained ventricular tachycardia (NSVT). Encainide efficacy was assessed during a dose-titration period and in a 36-month follow-up also studying the drug effects on routine haematologic data and left ventricular function (LVF). During dose-titration, encainide caused a 78.3% decrease in the average hourly frequency of isolated PVC and a 96.1% reduction in NSVT episodes in the two groups of patients. On follow-up (11 patients in each group) the mean percentage reductions were 95.1% in isolated PVC and 99.7% in NSVT episodes. Encainide did not impair LVF as showed by the comparison of echocardiographic fractional shortening before and after 12 months of treatment. Minor adverse effects of encainide were dose-related visual disturbances in two patients. A major adverse effect was the appearance of sustained VT in one NYHA class IV patient. Oral encainide effectively reduces the frequency of PVC and NSVT, it does not impair left ventricular function and it is associated with infrequent minor side effects. Uncommon, but severe, side effects may appear in patients with marked impairment of left ventricular function.