Post-Exercise Heart Rhythm Predicts Cardiovascular Risk
Study concludes post-exercise heart rhythm can predict risk of death in patients with heart disease
FRIDAY, March 27 (HealthDay News) -- Visible beat-to-beat alterations in cardiac repolarization known as T-wave alternans (TWA) predict the risk of cardiovascular disease and death in patients with coronary artery disease, according to a study in the March 31 issue of the Journal of the American College of Cardiology.
Michael P. Slawnych, M.D., Ph.D., from the University of Calgary in Alberta, Canada, and colleagues assessed TWA using the modified moving average method immediately after exercise in 1,003 patients with coronary artery disease.
During 48 months of follow-up, the researchers observed 54 deaths from cardiovascular disease. The risk of cardiovascular disease increased with increasing TWA, and TWA was as effective as ejection fraction in predicting cardiovascular disease. A 20-microvolt TWA cutoff had 87 percent sensitivity, which the authors suggest may be useful for higher-risk patients, while a 60-microvolt cutoff had a 95 percent specificity, which they suggest may be useful as a single test for lower-risk patients. Both cutoffs were independently associated with a 2.5-fold higher risk of cardiovascular disease.
"This analysis demonstrates that post-exercise assessment of TWA with use of the modified moving average method is a strong, independent predictor of cardiovascular disease and total mortality in patients with coronary artery disease," Slawnych and colleagues conclude.
One of the authors disclosed financial and consulting relationships with GE Healthcare and Cambridge Heart Inc.