Long-Term Suppression of Atrial Fibrillation by Botulinum Toxin Injection into Epicardial Fat Pads in Patients Undergoing Cardiac Surgery: One Year Follow Up of a Randomized Pilot Study

BACKGROUND—Animal models suggest that the neurotransmitter inhibitor, botulinum toxin, when injected into the epicardial fat pads can suppress atrial fibrillation (AF) inducibility. The aim of this prospective randomized double-blind study was to compare the efficacy and safety of botulinum toxin injection into epicardial fat pads for preventing atrial tachyarrhythmias. METHODS AND RESULTS—Patients with history of PAF and indication for coronary artery bypass graft (CABG) surgery were randomized to botulinum toxin (Xeomin, Merz, Germany; 50 U/1 mL at each fat pad; n=30) or placebo (0.9% normal saline, 1 mL at each fat pad; n=30) injection into epicardial fat pads during surgery. Patients were followed for 1-year to assess maintenance of sinus rhythm using an implantable loop recorder (ILR). All patients in both groups had successful epicardial fat pad injections without complications. The incidence of early postoperative AF within 30 days after CABG was 2 of 30 patients (7%) in the botulinum toxin group and 9 of 30 patients (30%) in the placebo group (P=0.024). Between 30 days and up to the 12-month follow-up examination, 7 of the 30 patients in the placebo group (27%) and none of the 30 patients in the botulinum toxin group (0%) had recurrent AF (P=0.002). There were no complications observed during the 1-year follow-up. CONCLUSIONS—Botulinum toxin injection into epicardial fat pads during CABG provided substantial atrial tachyarrhythmia suppression both early as well as during 1-year of follow-up, without any serious adverse events. CLINICAL TRIAL REGISTRATION—http://www.clinicaltrials.gov; Unique identifierNCT01842529.