Presentation Number:	1116-266
Abstract Title:	T Wave Alternans Predicts Arrhythmic Events in Patients With Congestive Heart Failure
Presentation Start/End Time:	Tuesday, Mar 08, 2005, 12:30 PM - 1:30 PM
Topic:	ECG/Ambulatory Monitoring Signal Averaging
Author Block:	Daniel M. Bloomfield, J. Thomas Bigger, Jr., Pearila Namerow, Richard Steinman, Michael Parides, TWA in CHF Investigators, Columbia University, New York, NY
We conducted a prospective longitudinal study to test the hypothesis that T wave alternans (TWA) is associated with an increased rate of arrhythmic events (AE) in patients with EF < 0.41. We previously reported that in a subset who met the MADIT II criteria, a TWA test identifies not only a high risk group, but also a low risk group unlikely to benefit from ICD therapy. In this report, we present the results of the entire study (including patients with ischemic (ISC) and non-ischemic (N-ISC) heart disease). Methods. Patients were eligible for this study if they had an EF < 0.41, were in sinus rhythm, had no history of a prior sustained AE, and were NYHA I-III. All patients underwent a TWA exercise test. Our composite endpoint includes all-cause mortality and non-fatal AE. Results. We studied 549 patients; 49% had ISC, the mean EF was 0.25, and 66% had an abnormal (positive or indeterminate) TWA test. Patients were followed for 2 years (average follow-up 20 months.) There were 51 endpoints (40 deaths and 11 non-fatal AE). Comparing patients with a normal to those with an abnormal TWA test, the hazard ratio for the composite endpoint was 6.5 (p < 0.001). The false negative rate of TWA was only 2%. The association between TWA and the composite endpoint was strong among patients with both ISC and N-ISC heart disease. Conclusion. Among patients with EF < 0.41 (ISC or N-ISC), TWA can identify a group at high risk of death or non-fatal AE, as well as a low risk group, which is likely to survive without an AE.