1. Does Microvolt T-Wave Alternans Testing Predict Ventricular Tachyarrhythmias in Patients With Ischemic Cardiomyopathy and Prophylactic Defibrillators?
- Author
-
Brett J. Peterson, John R. Onufer, Theodore Chow, Dean J. Kereiakes, Mark L. Brown, Alan Woelfel, Sinan Gursoy, David G. Benditt, Wenji Pu, and Master Trial Investigators
- Subjects
medicine.medical_specialty ,Ischemic cardiomyopathy ,Ejection fraction ,business.industry ,Hazard ratio ,T wave alternans ,medicine.disease ,Sudden death ,Confidence interval ,Internal medicine ,Cardiology ,Medicine ,Myocardial infarction ,Cardiology and Cardiovascular Medicine ,business ,Multicenter Automatic Defibrillator Implantation Trial - Abstract
Objectives The purpose of this trial was to determine whether microvolt T-wave alternans (MTWA) predicts ventricular tachyarrhythmic events (VTEs) in post-myocardial infarction patients with left ventricular ejection fraction (LVEF) ≤30%. Background Previous studies have established MTWA as a predictor for total and arrhythmic mortality, but its ability to identify prophylactic implantable cardioverter-defibrillator (ICD) recipients most likely to experience VTEs remains uncertain. Methods This prospective trial was conducted at 50 U.S. centers. Patients were eligible if they met MADIT-II (Multicenter Automatic Defibrillator Implantation Trial II) indications for device implant. All patients underwent MTWA testing followed by ICD implantation, with pre-specified programming to minimize the likelihood of therapies for non–life-threatening VTE. Minimum follow-up was 2 years with annual MTWA testing. Initially indeterminate MTWA tests were repeated. Results Analyses were conducted on 575 patients (84% male; average age ± SD = 65 ± 11 years; average LVEF ± SD = 0.24 ± 0.05). The final distribution of MTWA results were: MTWA positive in 293 (51%), MTWA negative in 214 (37%), and indeterminate in 68 patients (12%). Over an average follow-up of 2.1 ± 0.9 years, there were 70 VTEs. A VTE occurred in 48 of 361 (13%, 6.3%/year) MTWA non-negative and 22 of 214 (10%, 5.0%/year) MTWA negative patients. A non-negative MTWA test result was not associated with VTE (hazard ratio: 1.26; 95% confidence interval: 0.76 to 2.09; p = 0.37), although total mortality was significantly increased (hazard ratio: 2.04; 95% confidence interval: 1.10 to 3.78; p = 0.02). Conclusions In MADIT-II–indicated ICD-treated patients, the risk of VTE does not differ according to MTWA classification, despite differences in total mortality. (MASTER I–Microvolt T Wave Alternans Testing for Risk Stratification of Post MI Patients; NCT00305240 )
- Published
- 2008
- Full Text
- View/download PDF