Implantable Cardioverter-Defibrillator Shock Caused by Uncommon Variety of Nonreentrant Atrioventricular Nodal Tachycardia.

This article reports a typical case of incessant double-fire tachycardia resulting in implantable cardioverter-defibrillator discharge caused by the device's misdiagnosis of ventricular tachycardia. At electrophysiology study, the presence of double-fire physiology was confirmed, and modification of the slow pathway resulted in elimination of repetitive double fires. Although this is an unusual entity, it is important to recognize, because it may be misdiagnosed as atrial fibrillation, resulting in inappropriate anticoagulation and/or antiarrhythmic therapy. Modification of the slow pathway and elimination of double-fire physiology can result in marked improvement in quality of life and reversal of tachycardia-mediated cardiomyopathy.