Abstract
Repetitive nonreentrant ventriculo-atrial synchrony (RNRVAS) is an arrhythmia which occurs in patients with dual-chamber devices and requires an intact ventriculo-atrial conduction. It can present with symptoms similar to those of pacemaker-mediated endless loop tachycardia and is an example of functional atrial undersensing and functional loss of atrial capture. In addition to loss of optimal atrioventricular (AV) delay and inappropriate ventricular pacing, RNRVAS may trigger atrial arrhythmias and cause serious complications. We report a case of RNRVAS-induced atrial fibrillation (AF) terminated with implantable cardioverter defibrillator (ICD) shock in a 74-year old female with no prior history of AF.