In order to evaluate the incidence and prognostic value of ventricular arrhythmias in patients with aortic valve disease, 24 hour ambulatory electrocardiographic recordings were obtained in 374 patients without coronary artery disease (aortic stenosis n = 194, aortic regurgitation n = 103, combined aortic stenosis and regurgitation n = 77). Following aortic valve replacement, repeat recordings were obtained in a subgroup of 96 patients at 13 +/- 4 days and 18 +/- 7 months. Ventricular arrhythmias were classified in all cases according to Lown and were compared with clinical, echocardiographic and hemodynamic data. Preoperatively, ventricular premature beats were observed in 329 patients (88%), and were found to be frequent (>30 ventricular premature beats/hour) in 83 (22%). Multiformity was found in 105 (28%), couplets in 75 (20%) and ventricular tachycardia in 45 (12%). The occurrence of ventricular arrhythmias was not related to the type or severity of the valve lesions. Patients with severe ventricular arrhythmias (Lown class 3 or 4: 36.5%) had a higher ventricular wall thickness (interventricular septum thickness 14.2 +/- 1.8 mm vs. 11.9 +/- 2.0 mm, p < 0.01, a higher LV mass (178 +/- 32 g/m2 vs. 142 +/- 35 g/m2, p < 0.001) and a lower left ventricular ejection fraction (48% +/- 9% vs. 56.5% +/- 10%, p < 0.001); while in patients with aortic regurgitation a higher end-diastolic LV volume (224 +/- 38 ml/m2 vs. 178 +/- 42 ml/m2, p < 0.02) and a higher end-systolic LV diameter (56 +/- 7 mm vs. 46 +/- 8 mm, p < 0.02) were observed.(ABSTRACT TRUNCATED AT 250 WORDS)