HealthDay News — Intraoperative botulinum toxin (BTX) injections show promise as a way to reduce the risk for postoperative atrial fibrillation (AF) following cardiac surgery, according to two studies recently published in Heart Rhythm.
Alexander Romanov, M.D., from the E. Meshalkin National Medical Research Center of the Ministry of Health of the Russian Federation in Novosibirsk, and colleagues randomly assigned 60 patients with a history of paroxysmal AF and indications for coronary artery bypass grafting (CABG) to either BTX or placebo injections into four posterior epicardial fat pads during CABG. During three years of follow-up, the researchers found that the incidence of any atrial tachyarrhythmia was 23.3 percent in the BTX group versus 50 percent in the placebo group (hazard ratio [HR], 0.36; 95 percent confidence interval, 0.14 to 0.88; P = 0.02). At 12, 24, and 36 months, the AF burden was significantly lower in the BTX group than in the placebo group.
In the second article, Nathan H. Waldron, M.D., from Duke University in Durham, North Carolina, and colleagues randomly assigned 130 adults undergoing cardiac surgery (1:1) to intraoperative injection of 250 units of onabotulinumtoxinA or placebo into epicardial fat pads. The researchers found that 36.5 percent (23 of 63) of onabotulinumtoxinA-treated patients developed postoperative AF versus 47.8 percent (32 of 67) of placebo-treated patients (HR, 0.69; 95 percent confidence interval, 0.41 to 1.19; P = 0.18, in time-to-event analysis). There were no significant differences noted in postoperative hospital length of stay or adverse events prolonging length of stay between the groups.
“Future large-scale studies of epicardial onabotulinumtoxinA injection as a potential postoperative AF prevention strategy should be designed to study smaller, but clinically meaningful, treatment effects,” Waldron and colleagues write.
Several authors of the Waldron study disclosed financial ties to Allergan, which provided BTX for the study.