Programmed electrical stimulation in patients with high-grade ventricular ectopy: Electrophysiologic findings and prognosis for survival

The significance and treatment of ventricular premature beats (VPBs) in patients without sustained ventricular tachycardia (VT), sudden death, or syncope remains unclear. We undertook a prospective study of programmed electrical stimulation (up to two extrastimuli and burst pacing) in 73 patients (age 60 ± 10 years) with high-grade VPBs who had no evidence of sustained VT, sudden death, or syncope as determined by 48 hr of monitoring in the cardiac care unit and 48 hr Holter monitoring. Fifty-six patients (76.7%) had atherosclerotic heart disease, 10 (13.7%) had cardiomyopathy or valvular heart disease, and seven (9.6%) had no evident heart disease. Thirty-seven patients (50.7%) had Lown grade IVB VPBs, 30 (41.1%) had Lown grade IVA VPBs, and six (8.2%) had Lown grade III VPBs. Programmed electrical stimulation identified two groups of subjects: group 1 comprised 20 patients (27%) in whom VT or ventricular fibrillation was induced, group 2 comprised 53 patients (73%) in whom no ventricular arrhythmia or only two to four repetitive ventricular responses were induced. There was a significant difference between the presence of atherosclerotic heart disease, old myocardial infarction, and ejection fraction of less than 40% in group 1 compared with group 2. However, there was no significant difference in the grade of VPBs between the two groups. Seventeen of 20 patients from group 1 were placed on antiarrhythmic therapy (defined by programmed electrical stimulation), whereas group 2 patients were randomly assigned to prophylactic antiarrhythmic therapy. A total of 70 patients were followed up for 30 ± 15 months. The incidence of sustained VT and/or sudden death (31.5% vs 2%; p < .001) was significantly higher in group 1 compared with group 2. There was no difference in the occurrence of sudden or nonsudden cardiac death between the treated and untreated patients in group 2. The probability of surviving 1 year (0.75 vs 1.0) and 48 months (0.35 vs 0.67) was significantly lower (p < .0008) in group 1 than in group 2. In conclusion programmed electrical stimulation defines high- and low-risk subsets for sudden death among patients with high-grade VPBs. Patients in whom arrhythmias are not inducible and those with ejection fractions of greater than 40% have a low incidence of sudden death and an excellent 1 to 2 year survival; these patients do not need prophylactic antiarrhythmic therapy.