Microvolt T wave alternans testing does not identify which myocardial infarction survivors are most likely to develop ventricular arrhythmias and thus are candidates for implantable cardioverter defibrillators, according to a late-breaking clinical trial presentation at the annual meeting of the American Heart Association.

The MASTER I trial evaluated the Microvolt T Wave Alternans Test (MTWA) as a non-invasive alternative to electrophysiologic study. A total of 575 patients were enrolled from 50 medical centers in the United States. All patients met standard indications for prophylactic device implantation (primary prevention) and were not in atrial fibrillation.

“This was a community-based study so our findings should be applicable to everyday practice. Another strength of the study is that all patients received standardized treatment,” said Theodore Chow, the study’s principal investigator from the Lindner Center at The Christ Hospital, Cincinnati, Ohio. “Since patients had defibrillators in place as part of their routine therapy, the devices were programmed to provide safety and adequate data collection.”

The study’s most significant finding was that T-wave alternans testing did not identify those who were more likely to have life-threatening ventricular events during the follow-up period.

“We need to learn more about T Wave Alternans Testing before we can recommend it for routine clinical use,” Chow said.

For the present, he advises cardiologists to follow the American Heart Association/American College of Cardiology clinical guidelines for implanting devices.