Effect of oral β-blocker therapy on microvolt T-wave alternans and electrophysiology testing in patients with ischemic cardiomyopathy

Background: Prior investigation has shown that intravenous β-blockers decrease T-wave alternans (TWA) positivity in patients undergoing electrophysiology study (EPS). The present study examined whether oral β-blocker use within 24 hours of TWA influences yield and predictive value of TWA and EPS. Methods: We prospectively evaluated 387 patients (312 [81%] men, mean age 67 ± 11 years) with coronary artery disease, left ventricular ejection fraction ≤40%, and nonsustained ventricular tachycardia who underwent EPS and were followed for a mean of 2.8 ± 1.4 years. T-Wave alternans was performed using an atrial pacing protocol and interpreted using standard criteria. β-Blocker status was determined based on oral β-blocker use in the 24 hours preceding the test: β-blocker (-) (n = 62), β-blocker (+) (n = 325). Follow-up for ventricular tachycardia, ventricular fibrillation, and death was obtained from chart review, device interrogation, and the Social Security Death Index. Estimated sensitivity and specificity of TWA and EPS stratified by β-blocker use were calculated based on event-free 2-year survival. Results: There was no difference in EPS (31 [50%] inducible off β-blockers vs 166 [51%] on β-blockers [P = .89]) or TWA (26 [42%] positive, 17 [27%] indeterminate off β-blockers vs 136 [42%] positive, 81 [25%] indeterminate on β-blockers [P = .89]). β-Blocker use within 24 hours of testing did not affect the predictive value of TWA or EPS for overall or 2-year event-free survival. Conclusions: Oral β-blocker therapy appears to have no effect on yield or predictive value of EPS or TWA in patients with coronary artery disease, diminished left ventricular function, and a history of nonsustained ventricular tachycardia.