Implantable Cardioverter Defibrillator Sensing Failure Due to Endocardial R Wave Electrical Alternans

Authors

  • KRIT JONGNARANGSIN M.D.,

    1. *Cardiac Arrhythmia Service, Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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  • THEOFANIE MELA M.D.

    1. *Cardiac Arrhythmia Service, Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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Address for correspondence: Theofanie Mela, M.D., Cardiac Arrhythmia Service, Massachusetts General Hospital, 75 Fruit Street, Boston, MA 02114. Fax: 617-726-3852; E-mail: tmela@partners.org

Abstract

Electrical Alternans and ICD Undersensing. A 71-year-old patient underwent routine single-chamber implantable cardioverter defibrillator (ICD) generator replacement. During defibrillation threshold testing, ventricular tachycardia was induced but the ICD failed twice to properly detect the tachycardia due to endocardial R wave alternans and sensing of every other beat. The problem was resolved by inserting a separate sensing/pacing lead positioned further away from the existing ICD lead.

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