DefiPaceTM System, A New Device for Cardioversion of Atrial Fibrillation After Cardiac Surgery — Preliminary Results

Objectives: Postoperative atrial fibrillation (POAF) is a frequent complication following cardiac surgery. This study examined the safety and efficacy of the new DefiPaceTM system consisting of two bi-atrial temporary pacing and cardioversion electrodes, a ventricular electrode and the DefiPaceTM device (combined external pacemaker and cardioverter) for low-energy atrial cardioversion. Methods: The temporary electrodes were placed on the left and right atrium during open heart surgery. Pacing thresholds and sensing were measured up to the 6th postoperative day. The satisfactory handling of the electrodes was measured with a visual analog scale (VAS) 1–10, with 10 being the best and 1 being the lowest. In case of POAF, R-wave synchronous low-energy shocks (0.5–10 J) were applied for cardioversion. Results: Temporary electrodes were implanted in 29 patients (age 65.6 ± 10.4 years; 21 males, 14 OPCAB, 15 on-pump cardiac operations). Left or right atrial pacing thresholds ranged from 1.9 ± 1.3 V/ms to 5.0 ± 3.3 V/ms and P-wave sensing from 0.9 ± 0.6 mV to 1.5 ± 0.7 mV. VAS for handling of electrodes: implantation 7.1 ± 0.8 and removal 8.4 ± 1.0. POAF was observed in four patients. Two patients had successful atrial cardioversion with 3.5 J and 4.5 J. One patient converted spontaneously, and one patient remained in PAOF. There were no device-related adverse events. Conclusions: The DefiPaceTM system can be used safely in patients undergoing cardiac surgery.