[Spontaneous and stimulus-induced arrhythmia behavior in dilated cardiomyopathy]

To assess the incidence and significance of spontaneous and induced ventricular arrhythmias in idiopathic dilated cardiomyopathy, 24 h ambulatory electrocardiographic monitoring and programmed ventricular stimulation were performed in 52 patients. The mean left ventricular ejection fraction was 38 +/- 13%. Ventricular arrhythmias were present in 94%: 56% had non-sustained ventricular tachycardia with 3-20 consecutive VPCs and 17% ventricular pairs. In 56% of patients, more than 10(3) single VPCs/24 h were seen. Repetitive ventricular response was induced by programmed stimulation in 28 patients (54%): in 39%, 2-4 VPCs and in 15%, greater than or equal to 5 VPCs. In three patients (6%), sustained ventricular tachycardia (greater than or equal to 30 s) was initiated, which was of a monomorphic configuration in two of them. The incidence of induced ventricular arrhythmias could neither be correlated with the Lown grade of spontaneous arrhythmias nor with the total number of single VPCs/24 h. The inducibility of sustained ventricular tachycardia, however, was only seen in patients with arrhythmias of Lown grade IVb. No clear correlation could be determined between the impairment of left ventricular function and spontaneous or induced arrhythmias. During the 9-48 (median 34) months' follow-up, nine patients (17%) died, three of them died suddenly and five in congestive heart failure. All sudden cardiac death victims and three out of the five who died of congestive heart failure had non-sustained ventricular tachycardia during 24 h ambulatory electrocardiographic monitoring, but no higher incidence of single VPCs than the survivors. All patients who died had a significantly reduced left ventricular ejection fraction as compared to those who survived. In none of the patients who died were there more than three consecutive VPCs induced by programmed ventricular stimulation.