early recurrence of atrial fibrillation after ambulatory shock conversion

Objectives We sought to gain insights into the early recurrence of atrial fibrillation (ERAF) after cardioversion shocks delivered by permanently implanted rhythm management systems. Background Several reports have characterized ERAF, but these reports used a limited definition and did not evaluate an association between clinical or device variables and ERAF. Methods A total of 144 patients with recurrent, drug-resistant, symptomatic atrial fibrillation (AF) underwent implantation of an atrial rhythm management system (Medtronic Jewel AF, Model 7250, Minneapolis, Minnesota). The device was programmed to deliver cardioversion shocks automatically and/or on patient command. The incidence of ERAF was evaluated after 1,092 successful shocks among 97 patients. Three different ERAF definitions were used: recurrence within 1 min, 1 h or 1 day. Multiple clinical and device variables were assessed for their relationship with ERAF. Results The per-patient incidences of ERAF were 44%, 61% and 70% for ERAF within 1 min, 1 h and 1 day, respectively. The per-episode incidences of ERAF were 17%, 30% and 43% for ERAF within 1 min, 1 h and 1 day, respectively. Variables that were independently associated with ERAF included AF duration <3 h before termination, more than one shock required to cardiovert and the absence of a previous myocardial infarction. The most potent variable was AF duration <3 h, associated with a threefold increase in the incidence of ERAF. Conclusions Recurrence of AF early after ambulatory shock cardioversion is common. In this retrospective study, both clinical and device variables were predictive.