719-5 Clinical Correlates and Prognostic Significance of the Frequency of Episodes of Nonsustained Ventricular Tachycardia in the Electrophysiologic Study versus Electrocardiographic Monitoring Trial (ESVEM)

Abstract

Nonsustained ventricular tachycardia (VTns) predicts mortality in several settings but its significance in patients (pts) with a history of sustained ventricular tachyarrhythmias is unknown. Pts in ESVEM were randomized to guidance method and to drug independent of VTns events. We grouped pts (n = 486) by frequency of VTns events on baseline 48hr drug-free HM: Gl ≡ No VTns (n = 70), G2 ≡ >0 to <0.25 runs/h (n = 190). G3 ≡ ≥0.25 to <1 runs/h (n = 109), G4 ≡ ≥ 1 runs/h (n = 117). There were no significant differences (p > 0.05) between groups with respect to age, ejection fraction, functional class, presenting arrhythmia, prior exposure to antiarrhythmic drugs or guidance method. Data are presented in order of group number (Gr1, 2, 3, 4, respectively). Significant differences were observed for sex (29, 8, 13, 15%female; p = 0.0008), previous myocardial infarction (6%, 10%, 22%, 23%; p = 0.0002), PVC/h (136, 146, 300, 735; p < 0.0001), pairs/h (1, 3,12, 60; p < 0.0001), and mean heart rate (77, 74, 74, 80 bpm; p = 0.0008). Because the significance of VTns may vary in pts with different disorders, an analysis was restricted to pts with ischemic heart disease (IHD, n = 414). Significant differences were observed for age (63, 65, 64, 67 yr; p = 0.01). sex (23, 6, 10,9%female, p = 0.0028). years since last myocardial infarction (MI) (3.7, 8.9, 9.1, 7.9yr; p < 0.0001), history of operative revascularization (8%, 29%, 30%, 38%; p = 0.0003), for PVC/h (151, 149,286, 769 PVC/h; p < 0.0001). mean pairs/h (1, 3, 12,62; P < 0.0001). mean heart rate (76, 74, 76, 81 bpm; p = 0.004), but not for ejection fraction, functional class, presenting arrhythmia, previous exposure to antiarrhythmic drugs, number of Mis, or angina since last MI. Variables based on presence/absence, on continuous and on stratified frequency measures of VTns events and the above variables were entered into a Cox proportional hazards regression model for: 1) pts discharged on a drug predicted to be effective, 2) all randomized pts (intention-to-treat), 3) pts with IHD. None of the VTns variables were significant independent predictors of arrhythmia recurrence or all-cause mortality. We conclude that significant clinical differences exist between groups of pts with different frequencies of VTns events. However, measures of VTns event frequency were not predictors of arrhythmia recurrence or mortality in this group of patients with known ventricular tachyarrhythmias.