Treatment of Patients with Myocardial Infarction Who Present with a Paced Rhythm

17 April 2001 | Volume 134 Issue 8 | Pages 644-651

Background: A paced rhythm can mask the electrocardiographic features of an acute myocardial infarction, complicating timely recognition and treatment.

Objective: To evaluate characteristics, treatment, and outcomes among patients presenting with paced rhythms during myocardial infarction.

Design: Retrospective cohort study.

Setting: U.S. acute care hospitals.

Patients: 102 249 Medicare beneficiaries at least 65 years of age who were treated for acute myocardial infarction between 1994 and 1996.

Measurements: Provision of three treatments for acute myocardial infarction (emergent reperfusion, aspirin, and ß-blockers), death at 30 days, and long-term follow-up.

Results: 1954 patients (1.9%) presented with paced rhythms during myocardial infarction. These patients were older; were predominantly male; and had higher rates of congestive heart failure, diabetes, and previous infarction. They were significantly less likely to receive emergent reperfusion (relative risk [RR], 0.27 [95% CI, 0.22 to 0.33]), aspirin (RR at admission, 0.91 [CI, 0.88 to 0.94]; RR at discharge, 0.87 [CI, 0.83 to 0.92]), and ß-blockers at admission (RR, 0.89 [CI, 0.82 to 0.96]). In addition, there was a trend toward decreased use of ß-blockers at discharge (RR, 0.91 [CI, 0.76 to 1.06]). Crude mortality rates were higher among patients with paced rhythms than among those without at 30 days (25.8% vs. 21.3%; P = 0.001) and at 1 year (47.1% vs. 36.1%; P = 0.001). Among patients with paced rhythms, risk for death at 30 days decreased after adjustment for illness severity and decreased use of therapy (RR, 1.03 [CI, 0.93 to 1.14]). Patients with paced rhythms remained at additional risk for long-term mortality (hazard ratio, 1.12 [CI, 1.06 to 1.18]).

Conclusions: Patients with paced rhythms were less likely than those without to receive treatment for acute myocardial infarction and had poorer short- and long-term outcomes. However, this mortality risk diminished after adjustment for treatment. This suggests that improved recognition and treatment of myocardial infarction may improve outcomes, particularly in the short term.

Author and Article Information

From Georgetown University Medical Center, Washington, D.C.; Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina; Mayo Clinic and Foundation, Rochester, Minnesota; Maryland HealthCare Associates, Clinton, Maryland; and Delmarva Foundation for Medical Care, Easton, Maryland.

Disclaimer: The analyses on which this publication is based were performed under contract numbers 500-96-P623 and 500-96-P624, titled "Utilization and Quality Control Peer Review Organization for the State of Maryland and the District of Columbia," sponsored by the Delmarva Foundation for Medical Care, Inc., and the Health Care Financing Administration, U.S. Department of Health and Human Services. The contents of this publication do not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. government. The authors assume full responsibility for the accuracy and completeness of the ideas presented. The article is a direct result of the Health Care Quality Improvement Program initiated by the Health Care Financing Administration, which has encouraged identification of quality improvement projects derived from analysis of patterns of care.

Requests for Single Reprints: Allen J. Solomon, MD, Division of Cardiology, Georgetown University Medical Center, Room M4222, 3800 Reservoir Road NW, Washington, DC 20007; e-mail, solomona{at}gunet.georgetown.edu.

Current Author Addresses: Mr. Rathore: Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, Room IE-61 SHM, Box 208025, New Haven, CT 06520-8025.

Drs. Weinfurt and Schulman: Center for Clinical and Genetic Economics, Duke Clinical Research Institute, Box 17969, Duke University Medical Center, Durham, NC 27715.

Dr. Gersh: Division of Internal Medicine and Cardiovascular Diseases, Mayo Clinic, Suite 1643, 2001 First Street SW, Rochester, MN 55902.

Dr. Oetgen: Maryland HealthCare Associates, Suite 600, 9131 Piscataway Road, Clinton, MD 20735.

Dr. Solomon: Division of Cardiology, Georgetown University Medical Center, Room M4222, 3800 Reservoir Road NW, Washington, DC 20007.

Author Contributions: Conception and design: S.S. Rathore, A.J. Solomon.

Analysis and interpretation of the data: S.S. Rathore.

Drafting of the article: S.S. Rathore, B.J. Gersh, W.J. Oetgen, A.J. Solomon.

Critical revision of the article for important intellectual content: S.S. Rathore, K.P. Weinfurt, B.J. Gersh, W.J. Oetgen, K.A. Schulman, A.J. Solomon.

Final approval of the article: S.S. Rathore, K.P. Weinfurt, B.J. Gersh, W.J. Oetgen, K.A. Schulman, A.J. Solomon.

Provision of study materials or patients: W.J. Oetgen, K.A. Schulman, A.J. Solomon.

Statistical expertise: S.S. Rathore, K.P. Weinfurt.

Obtaining of funding: B.J. Gersh, W.J. Oetgen, K.A. Schulman, A.J. Solomon.

Administrative, technical, or logistic support: S.S. Rathore, W.J. Oetgen, A.J. Solomon.