title: Effect of oral beta-blocker therapy on microvolt T-wave alternans and electrophysiology testing in patients with ischemic cardiomyopathy.
abstract: BACKGROUND
  Prior investigation has shown that intravenous beta-blockers decrease T-wave alternans (TWA) positivity in patients undergoing electrophysiology study (EPS). The present study examined whether oral beta-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 < or = 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. Beta-blocker status was determined based on oral beta-blocker use in the 24 hours preceding the test: beta-blocker (-) (n = 62), beta-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 beta-blocker use were calculated based on event-free 2-year survival.
  
  
  RESULTS
  There was no difference in EPS (31 [50%] inducible off beta-blockers vs 166 [51%] on beta-blockers [P = .89]) or TWA (26 [42%] positive, 17 [27%] indeterminate off beta-blockers vs 136 [42%] positive, 81 [25%] indeterminate on beta-blockers [P = .89]). Beta-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 beta-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.
authors.affiliation: Maurice and Corinne Greenberg Division of Cardiology, Department of Medicine, Cornell University Medical Center, New York, NY 10021, USA.
authors.forename: Eran S
authors.initials: ES
authors.lastname: Zacks
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Morin
authors.forename: Shaun
authors.initials: S
authors.lastname: Ageno
authors.forename: Matthew
authors.initials: M
authors.lastname: Janik
authors.forename: Andreas C
authors.initials: AC
authors.lastname: Mauer
authors.forename: Steven M
authors.initials: SM
authors.lastname: Markowitz
authors.forename: Suneet
authors.initials: S
authors.lastname: Mittal
authors.forename: Sei
authors.initials: S
authors.lastname: Iwai
authors.forename: Bindi K
authors.initials: BK
authors.lastname: Shah
authors.forename: Bruce B
authors.initials: BB
authors.lastname: Lerman
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Stein
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis*; D002304:Cardiac Pacing, Artificial; D009202:Cardiomyopathies / Q000401:mortality / Q000503:physiopathology*; D018572:Disease-Free Survival; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000401:mortality / Q000503:physiopathology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology; D014693:Ventricular Fibrillation / Q000175:diagnosis
chemical_list: D000319:Adrenergic beta-Antagonists