Association of Electrocardiographic Morphology of Exercise-Induced Ventricular Arrhythmia with Mortality

7 October 2008 | Volume 149 Issue 7 | Pages 451-460

Background: The prognostic importance of exercise-induced ventricular arrhythmia (EIVA) may be confounded by the presence of lower-risk idiopathic right ventricular outflow tract arrhythmias with left bundle-branch block (LBBB) morphology.

Objective: To determine whether right bundle-branch block (RBBB)–morphology EIVA was associated with increased mortality.

Design: Retrospective cohort.

Setting: Academic medical center.

Patients: 585 unique patients with EIVA and 2340 patients without EIVA, matched by age, sex, and risk factor, who were referred for exercise testing in an academic medical center.

Measurements: Deaths and ischemia and infarction found on perfusion scan.

Results: During a mean follow-up of 24 months (SD, 13), 31 deaths occurred in the EIVA group compared with 43 deaths in the group without EIVA (5.3% vs. 1.8%; P < 0.001). Worse survival in patients with RBBB-morphology or multiple-morphology EIVA (6.9%) than in patients without EIVA caused this difference. Patients with LBBB-morphology EIVAs had a mortality rate (2.5%) similar to that of patients without EIVA (P = 0.93, log-rank test). Among patients without known atherosclerotic coronary artery disease, any RBBB-morphology EIVA was associated with death (hazard ratio, 2.73 [95% CI, 1.78 to 4.13]; P < 0.001), but LBBB-morphology EIVA was not (hazard ratio, 0.82 [CI, 0.18 to 2.04]; P = 0.72).

Limitations: Not all LBBB-morphology EIVA can be dismissed, and not all RBBB-morphology EIVA is high risk. Further evaluation of patients for structural heart disease was clinically driven, not protocol-driven.

Conclusion: Right bundle-branch block– or multiple-morphology EIVA is associated with increased mortality. Inclusion of patients with isolated LBBB-morphology EIVA, which often is idiopathic, may contribute to differences in the prognostic importance of EIVA in previous studies.

Editors' Notes Context The prognostic value of exercise-induced ventricular arrhythmia (EIVA) is uncertain. The relationship of EIVA to outcomes may vary with EIVA morphologic characteristics (left or right bundle-branch block). Contribution This study of patients who had exercise testing from January 2001 to March 2006 evaluated survival in 585 patients with EIVA and 2340 patients without EIVA, matched by age, sex, and risk factor. Over an average of 24 months, 5.3% of patients with EIVA and 1.8% without EIVA died. However, only patients with any right bundle-branch block morphology EIVA had a higher risk for death than those without EIVA. Implication Patients with right bundle-branch block–morphology EIVA, but not those with left-bundle branch–morphology EIVA, have worse survival than patients without EIVA. —The Editors

 

Author and Article Information

From Brooke Army Medical Center, San Antonio, Texas; Brigham and Women's Hospital, Boston Veterans Administration Medical Center, and Beth Israel Deaconess Medical Center, Boston, Massachusetts; and the University of Alberta, Edmonton, Alberta, Canada.

Potential Financial Conflicts of Interest: Honoraria: L.M. Epstein (Medtronic, Boston Scientific, St. Jude). Grants received: L.M. Epstein (Medtronic, Boston Scientific, Biosense Webster).

Reproducible Research Statement: Study protocol: Available from Brigham and Women's Hospital Institutional Review Board, 75 Francis Street, Boston, MA 02115. Statistical code: Available from Dr. Eckart (e-mail, robert.eckart{at}us.army.mil). Data set: Certain portions of the analytic data set are available to approved individuals through written agreements with Dr. Eckart (e-mail, robert.eckart{at}us.army.mil).

Requests for Single Reprints: MAJ Robert E. Eckart, MC, USA, Arrhythmia Service (ATTN: MCHE-MDC), 3851 Roger Brooke Drive, Brooke Army Medical Center, San Antonio, TX 78234; e-mail, robert.eckart{at}us.army.mil.

Current Author Addresses: Dr. Eckart: Arrhythmia Service (ATTN: MCHE-MDC), 3851 Roger Brooke Drive, Brooke Army Medical Center, San Antonio, TX 78234.

Dr. Field: Cardiovascular Consultants of Maine, P.A., 96 Campus Drive, Suite 1, Scarborough, ME 04074.

Dr. Hruczkowski: Cardiology Arrhythmia Services, 2C1.16 Walter Mackenzie Centre, University of Alberta, Edmonton, Alberta T6G 2B7, Canada.

Drs. Forman, Dorbala, Di Carli, Albert, Epstein, and Stevenson: Cardiovascular Division, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115.

Dr. Maisel: Cardiovascular Division, Beth Israel Deaconess Medical Center, 185 Pilgrim Road, Baker 4, Boston, MA 02215.

Author Contributions: Conception and design: R.E. Eckart, M.E. Field, C.E. Albert, W.H. Maisel, L.M. Epsteìn, W.G. Stevenson.

Analysis and interpretation of the data: R.E. Eckart, M.E. Field, T.W. Hruczkowski, M.F. Di Carli, C.E. Albert, W.H. Maisel.

Drafting of the article: R.E. Eckart, M.E. Field, T.W. Hruczkowski, M.F. Di Carli, W.H. Maisel, L.M. Epsteìn.

Critical revision of the article for important intellectual content: R.E. Eckart, S. Dorbala, M.F. Di Carli, C.E. Albert, W.H. Maisel, L.M. Epsteìn, W.G. Stevenson.

Final approval of the article: R.E. Eckart, S. Dorbala, M.F. Di Carli, W.H. Maisel, L.M. Epsteìn, W.G. Stevenson.

Provision of study materials or patients: R.E. Eckart, S. Dorbala, M.F. Di Carli, L.M. Epsteìn.

Statistical expertise: R.E. Eckart, W.H. Maisel.

Obtaining of funding: R.E. Eckart.

Administrative, technical, or logistic support: R.E. Eckart.

Collection and assembly of data: R.E. Eckart, T.W. Hruczkowskì, M.F. Di Carli.