Wide Complex Tachycardia in the Presence of Class I Antiarrhythmic Agents: A Diagnostic Challenge

Authors

  • Bhaskar Bhardwaj M.D.,

    1. Department of Medicine, Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, OK
    Search for more papers by this author
  • Ralph Lazzara M.D.,

    1. Department of Medicine, Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, OK
    Search for more papers by this author
  • Stavros Stavrakis M.D. Ph.D.

    Corresponding author
    1. Department of Medicine, Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, OK
    • Address for correspondence: Stavros Stavrakis, M.D., Ph.D.,University of Oklahoma Health Sciences Center, 1200 Everett Dr., 6E103, Oklahoma City, OK 73104. Fax: 405-271-7455; E-mail: stavros-stavrakis@ouhsc.edu

    Search for more papers by this author

  • Conflict of interest: none.

Abstract

We present two patients with paroxysmal atrial fibrillation on class 1C antiarrhythmic drugs without concomitant atrioventricular (AV) nodal blocking agents who developed atrial flutter with 1:1 AV conduction. Their electrocardiogram revealed wide complex tachycardia with rates >200/minute. Atrial flutter with 1:1 conduction in the presence of class IC antiarrhythmic drugs may present a diagnostic challenge. These cases illustrate the importance of coadministering an AV nodal blocking agent with class IC antiarrhythmic agents in patients with atrial fibrillation. The differential diagnosis of wide complex tachycardia in patients taking class IC agents should include atrial flutter with 1:1 AV conduction.

Ancillary