Induction of atrial fibrillation with rapid high voltage ventricular pacing for ventricular fibrillation conversion testing

Objective-To assess whether rapid high voltage ventricular paring ran also induce atrial fibrillation, and whether the induction of atrial fibrillatio n during ventricular fibrillation conversion testing is related to the pati ent's heart disease. Design-Prospective study of 50 patients who received the dual chamber impla ntable cardioverter-defibrillator (ICD) Ventak AV Pi DR (Guidant) as a firs t implant. This device can record atrial activity even during a ventricular fibrillation episode and can induce atrial fibrillation by rapid atrial bu rsts. Main outcome measures-Frequency of atrial fibrillation after induction of v entricular fibrillation; clinical characteristics of patients with and with out induced atrial fibrillation; frequency of atrial fibrillation induced b y rapid atrial bursts during predischarge testing. Results-Atrial fibrillation was observed in 40 of the 217 ventricular fibri llation episodes (18%) that could be detected immediately after delivery of high voltage pacing. The biphasic ICD shock for termination of ventricular fibrillation also terminated the atrial fibrillation in all cases. The 40 episodes of simultaneous atrial and ventricular fibrillation occurred in 18 patients (36%). The distribution of the clinical characteristics of the pa tients and the inducibility of atrial fibrillation during predischarge test ing were similar in those with and without induced atrial fibrillation. Conclusions-Rapid high voltage ventricular pacing frequently induces atrial fibrillation, which was terminated by the subsequent biphasic ICD shock. T he induction of atrial fibrillation seems to be a non-specific phenomenon, unrelated to the clinical status of the patient.