Effect of bundle branch block on microvolt T-wave alternans and electrophysiologic testing in patients with ischemic cardiomyopathy

Morin, Daniel P., Zacks, Eran S., Mauer, Andreas C., Ageno, Shaun, Janik, Matthew, Markowitz, Steven M., Mittal, Suneet, Iwai, Sei, Shah, Bindi K., Lerman, Bruce B. and Stein, Kenneth M. (2007) Effect of bundle branch block on microvolt T-wave alternans and electrophysiologic testing in patients with ischemic cardiomyopathy. Heart Rhythm, 4 7: 904-912. doi:10.1016/j.hrthm.2007.02.027


Author Morin, Daniel P.
Zacks, Eran S.
Mauer, Andreas C.
Ageno, Shaun
Janik, Matthew
Markowitz, Steven M.
Mittal, Suneet
Iwai, Sei
Shah, Bindi K.
Lerman, Bruce B.
Stein, Kenneth M.
Title Effect of bundle branch block on microvolt T-wave alternans and electrophysiologic testing in patients with ischemic cardiomyopathy
Journal name Heart Rhythm   Check publisher's open access policy
ISSN 1547-5271
1556-3871
Publication date 2007-07
Sub-type Article (original research)
DOI 10.1016/j.hrthm.2007.02.027
Volume 4
Issue 7
Start page 904
End page 912
Total pages 9
Place of publication Philadelphia, PA, United States
Publisher Elsevier
Language eng
Formatted abstract
Background

T-wave alternans (TWA) and electrophysiology study (EPS) are used for risk stratification for sudden death.
Objective

The purpose of the study was to determine the effect of bundle branch block or intraventricular conduction delay on TWA and EPS.
Methods

386 patients with coronary artery disease, nonsustained ventricular tachycardia, and left ventricular ejection fraction ≤40% underwent TWA and EPS, and were followed for 40 ± 19 months.
Results

Patients with wide QRS were more likely than narrow QRS patients to have nonnegative TWA (77% vs 63%, P <.01) or positive EPS (60% vs 48%, P = .03). Nonnegative TWA predicted the combined endpoint of ventricular tachyarrhythmia or death in narrow QRS (HR = 1.64, P = .04) but not wide QRS patients (HR = 1.04, P = .91). Similarly, positive EPS predicted the combined endpoint in narrow QRS (HR = 2.28, P <.001) but not wide QRS patients (HR = 0.94, P = .84). In multivariate analysis, QRS width and TWA, as well as QRS width and EPS, were independent predictors of events. There was no TWA- or EPS-based difference in arrhythmia-free survival within any specific wide QRS morphology.
Conclusion

TWA and EPS are more often abnormal in patients with a wide QRS than in those with a narrow QRS. In patients with narrow QRS, both TWA and EPS stratify patients according to their risk of ventricular tachyarrhythmia or death. However, among patients with a wide QRS, regardless of specific QRS morphology, the risk is high and comparable regardless of TWA or EPS results. Therefore, the only truly low-risk group consists of those patients with negative test results and a narrow QRS.
Keyword T-wave alternans
electrophysiologic study
bundle branch block
Qrs
Left-Ventricular Dysfunction
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: ERA 2012 Admin Only
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