Risk stratification and management of patients with organic heart disease and nonsustained ventricular tachycardia: role of programmed stimulation, left ventricular ejection fraction, and the signal-averaged electrocardiogram

Abstract

Purpose: Programmed stimulation, left ventricular ejection fraction, and signal-averaged electrocardiography were performed in patients with organic heart disease and spontaneous nonsustained ventricular tachycardia (VT) to determine the role of these techniques in risk stratification and management.

Patients and methods: The study consisted of 90 patients: 63 had coronary artery disease and 27 had idiopathic dilated cardiomyopathy. Radionuclide ventriculography, signal-averaged electrocardiography, and programmed electrical stimulation were performed in all patients within 48 hours of index ambulatory electrocardiography.

Results: Fifty-three patients (59%) had an ejection fraction less than 40%. Programmed stimulation induced sustained monomorphic VT in 22 patients (24%), ventricular fibrillation (VF) in 10 patients (11%), and no sustained VT/VF in 58 patients (64%). The signal-averaged electrocardiogram (ECG) showed late potentials in 23 patients (26%). Sustained monomorphic VT could be induced in 65% of patients with late potentials and in 10% of those without late potentials. There was no case of inducible sustained monomorphic VT in 33 patients with no late potentials and an ejection fraction of 40% or greater. All patients with induced sustained monomorphic VT received antiarrhythmic therapy guided by the results of programmed stimulation. All 58 patients with no induced sustained ventricular tachyarrhythmias and eight patients with induced VF were discharged without receiving antiarrhythmic drugs. During a follow-up of 30 +/- 10 months, the three-year sudden death rate was 19% in patients with induced sustained VT, 0% in those with induced VF, and 9% in those with no induced sustained VT/VF. The three-year sudden death rate was the same (7%) in patients with no induced sustained VT/VF, both in those with an ejection fraction of 40% or greater or less than 40%. On the other hand, the three-year total cardiac mortality was significantly higher (27%) in those patients with ejection fractions less than 40% compared to those with ejection fractions of 40% or greater (7%).

Conclusion: It is concluded that the signal-averaged ECG, ejection fraction, and programmed stimulation could be used for the risk stratification and management of patients with organic heart disease and nonsustained VT as follows: (1) Patients with no late potentials and with an ejection fraction of 40% or greater do not require invasive evaluation or antiarrhythmic therapy, since the incidences of induced VT and sudden death are very low. (2) Patients with late potentials as well as patients without late potentials but with an ejection fraction of less than 40% may be advised to undergo electrophysiologic evaluation.(ABSTRACT TRUNCATED AT 400 WORDS)