A New Attempt to Scrutinize the Culprit CFAE Using Antiarrhythmic Drugs Aiming at Optimal Defragmentation

Abstract

Background: Ablation of complex fractionated atrial electrograms (CFAE) is now performed in patients with persistent atrial fibrillation (AF). However, extensive ablation is often necessary to eliminate all CFAE or to terminate AF. The purpose of this study was to evaluate the effects of antiarrhythmic drug on CFAE. Methods and Results: Thirty patients, including 19 with longstanding persistent AF and 11 with persistent AF, underwent box isolation. After box isolation, CFAE maps were created before and after infusion of a pure IKr blocker, nifekalant (0.3 mg/kg). Nifekalant terminated AF in 10 (33%) patients. In the remaining patients, nifekalant prolonged the mean AF cycle length (from 149 to 212 ms, p<0.0001) and decreased the proportion of CFAE. Ablation of CFAE localized by nifekalant terminated AF in 8 (27%) patients. After a single ablation procedure, 2 of 18 patients (11%) with AF termination showed a recurrence of AF. In contrast, 6 of 12 (50%) patients without AF termination showed a recurrence of AF. A second ablation procedure was performed in 6 patients. At 12±3 months after the last ablation procedure, 28 (93%) patients were free of AF. Conclusions: Nifekalant may scrutinize the culprit CFAE. This approach may be feasible and effective for decreasing the unnecessary ablation of bystander CFAE.