02 feb 2009-- Anger-induced T-wave alternans, a marker of repolarization instability, predicts ventricular arrhythmias in patients with implantable cardioverter-defibrillators (ICDs), providing a link between stress and sudden death, according to a report in the Mar. 3 issue of the Journal of the American College of Cardiology.
Rachel Lampert, M.D., from Yale University School of Medicine in New Haven, Conn., and colleagues determined whether T-wave alternans induced during a mental stress protocol could predict ventricular arrhythmias in 62 patients with ICDs.
During a follow-up of at least one year, the researchers found that the 10 patients with ICD-terminated arrhythmias had significantly higher anger-induced T-wave alternans (13.2 versus 9.3 microvolts). Arrhythmias were more common in patients in the highest quartile of anger-induced T-wave alternans (greater than 11.9 microvolts) on extended follow-up (40 versus 9 percent), the investigators report. After controlling for confounding factors, anger-induced T-wave alternans was an independent predictor of ICD-terminated arrhythmia, with patients in the highest quartile having a 10.8-fold higher risk of arrhythmia, the authors write.
"The investigators provide the first evidence that patients with higher levels of anger-induced T-wave alternans during provocative testing are at greater risk for ventricular arrhythmias detected by ICDs during follow-up," Eric J. Rashba, M.D., from Stony Brook University Medical Center in Stony Brook, N.Y., writes in an accompanying editorial.
PinMed Inc. provided the repolarization analysis software used in the study, and two of the study authors are employees of the company and one has a significant ownership stake. Authors of the study and editorial report relationships with device companies.