CLINICAL RESEARCH: CLINICAL TRIAL
Does Microvolt T-Wave Alternans Testing Predict Ventricular Tachyarrhythmias in Patients With Ischemic Cardiomyopathy and Prophylactic Defibrillators?The MASTER (Microvolt T Wave Alternans Testing for Risk Stratification of Post-Myocardial Infarction Patients) Trial
Theodore Chow, MD, FACC*,*,
Dean J. Kereiakes, MD, FACC*,
John Onufer, MD ,
Alan Woelfel, MD ,
Sinan Gursoy, MD ,
Brett J. Peterson, BS||,
Mark L. Brown, PhD||,
Wenji Pu, PhD||,
David G. Benditt, MD¶ on behalf of the MASTER Trial Investigators
* The Lindner Clinical Trial Center at The Christ Hospital, Cincinnati, Ohio
Cardiovascular Associates, Ltd., Chesapeake, Virginia
West Michigan Heart, Grand Rapids, Michigan
Naples Community Hospital, Naples, Florida
|| Medtronic, Inc., Minneapolis, Minnesota
¶ University of Minnesota, Minneapolis, Minnesota
Manuscript received March 5, 2008;
revised manuscript received August 8, 2008,
accepted August 11, 2008.
* Reprint requests and correspondence: Dr. Theodore Chow, Director of Electrophysiology Research, Lindner Center at The Christ Hospital, 2123 Auburn Avenue, Suite 424, Cincinnati, Ohio 45219 (Email: Chowt{at}ohioheart.org).
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)
Key Words: defibrillator therapy • risk stratification • sudden death • T-wave alternans • ventricular arrhythmias
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Abbreviations and Acronyms
| | CHF = congestive heart failure | | CI = confidence interval | | CRT = cardiac resynchronization therapy | | HR = hazard ratio | | ICD = implantable cardioverter-defibrillator | | LVEF = left ventricular ejection fraction | | MTWA = microvolt T-wave alternans | | NYHA = New York Heart Association | | SCD = sudden cardiac death | | VTE = ventricular tachyarrhythmic event |
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J. Am. Coll. Cardiol. 2008 52: A28.
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