Long QT Syndrome in Patients over 40 Years of Age: Increased Risk for LQTS-Related Cardiac Events in Patients with Coronary Disease

Authors

  • Edward Sze B.A.,

    1. Cardiology Division of the Department of Medicine
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  • Arthur J. Moss M.D.,

    1. Cardiology Division of the Department of Medicine
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  • Ilan Goldenberg M.D.,

    1. Cardiology Division of the Department of Medicine
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  • Scott McNitt M.S.,

    1. Cardiology Division of the Department of Medicine
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  • Christian Jons M.D.,

    1. Cardiology Division of the Department of Medicine
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  • Wojciech Zareba M.D., Ph.D.,

    1. Cardiology Division of the Department of Medicine
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  • Ming Qi Ph.D.,

    1. the Department of Pathology, University of Rochester School of Medicine and Dentistry, Rochester, NY
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  • Jennifer L. Robinson M.S.,

    1. Cardiology Division of the Department of Medicine
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  • for the International Long QT Syndrome Investigative Group

    1. The Long QT Syndrome Investigative Group includes: Michael J. Ackerman, M.D., Ph.D. (Mayo Clinic College of Medicine, Rochester, MN), Jesaia Benhorin, M.D. (Bikur Cholim Hospital, Jerusalem, Israel), Elizabeth Kaufman, M.D. (MetroHealth Campus, Case Western Reserve University, Cleveland OH, Emanuela Locati, M.D., Ph.D. (Niguarda Hospital, Milan Italy), Carlo Napolitano, M.D., and Silvia Priori, M.D., Ph.D. (Fondazione S. Maugeri-University of Pavia, Pavia, Italy), Peter J. Schwartz, M.D., and Carla Spazzolini, M.S. (Policlinico S. Matteo IRCCS, University of Pavia, Pavia, Italy), Jeffrey Towbin, M.D. (Baylor College of Medicine, Houston, TX), G. Michael Vincent, M.D., and Li Zhang, M.D. (University of Utah Medical School, Salt Lake City, UT).
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  • Supported in part by research grants HL-33843 and HL-51618 from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, M.D.

Address for reprints: Arthur J. Moss, M.D., Heart Research Follow-up Program, University of Rochester Medical Center, 601 Elmwood Avenue, Box 653, Rochester, NY 14642-8653. Fax: 585-273-5283; E-mail: heartajm@heart.rochester.edu

Abstract

Background: Previous studies of long QT syndrome (LQTS) have focused primarily on the clinical course of affected patients up to 40 years of age to avoid the confounding influence of acquired heart disease on LQTS-related cardiac events in this genetic disorder.

Methods: Patients were identified as having coronary disease if they had a history of hospitalization for myocardial infarction, coronary angioplasty, coronary artery bypass graft surgery, or were treated with medication for angina. LQTS-related cardiac events included the first occurrence of syncope, aborted cardiac arrest, or sudden cardiac death without evidence suggestive of an acute coronary event. Cox proportional hazards regression modeling was used to analyze the independent contribution of coronary disease to LQTS-related cardiac events.

Results: Time-dependent coronary disease was associated with an increased risk of LQTS-related cardiac events (hazard ratio 2.24, 95% confidence interval 1.23–4.07, P = 0.008) after adjustment for syncopal history before age 40, QTc, and gender. Factors such as diabetes and hypertension that increase the risk for coronary disease were not associated with an increased risk for LQTS-related cardiac events.

Conclusions: This is the first study to demonstrate that coronary disease augments the risk for LQTS-related cardiac events in LQTS. The findings highlight the need for more focused preventive therapy in LQTS patients above the age of 40.

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