Botulinum toxin suppression of AF maintained at 3 years
BOSTON — Patients who received an injection of botulinum toxin into epicardial fat pads during CABG had lower incidence of atrial tachyarrhythmias and reduced atrial fibrillation burden at 3 years vs. placebo, researchers reported at the Heart Rhythm Society Annual Scientific Sessions.
As Cardiology Today previously reported, when researchers randomly assigned 60 patients (mean age, 63 years; 20% women) with paroxysmal AF and an indication for CABG to an injection of botulinum toxin (Xeomin, Merz Pharmaceuticals) 50 U/1 mL at each fat pad or placebo (0.9% normal saline, 1 mL at each fat pad) during surgery, the botulinum toxin group had less AF recurrence and burden at 1 year.
In a presentation here, Alexander Romanov, MD, PhD, FHRS, from the E. Meshalkin National Medical Research Center of the Ministry of Health of the Russian Federation in Novosibirsk, Russia, said the results were sustained out to 3 years, despite the botulinum toxin having long disappeared from patients’ systems.
“Botulinum toxin can be viewed as a neuromodulator, and thus differs from the neurodestructive effects of other therapeutic efforts,” Romanov said during the presentation. “Because the favorable reduction of atrial fibrillation outlasted the anticipated botulinum toxin effect on the autonomic nervous system activity, this may represent a form of autonomic reverse remodeling.”
Botulinum toxin is also used for facial injections and to treat muscle stiffness/spasms and migraines.
At 3 years, the primary endpoint of any atrial tachyarrhythmia including AF with a monthly burden exceeding 0.5% without use of antiarrhythmic drugs occurred in 23% of the botulinum toxin group vs. 50% of the placebo group (HR = 0.36; 95% CI, 0.14-0.88), according to the researchers.
The botulinum toxin group also had fewer patients hospitalized (P = .02), fewer total hospitalizations (P < .001) and less antiarrhythmic drug use (P = .029) vs. the placebo group, Romanov said, noting there were also trends that favored the botulinum group for new endocardial AF ablation, thrombo-embolic events and death, but these did not reach statistical significance.
Also at 3 years, AF burden was 1.3% in the botulinum toxin group vs. 6.9% in the placebo group (P = .007), he said.
A larger study, sponsored by Allergan, has been commenced to confirm the findings and will include patients undergoing valve surgery as well as those undergoing CABG, Romanov said. – by Erik Swain
Romanov A, et al. LBCT02-01. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 9-12, 2018; Boston.
Disclosure: Romanov reports he serves on the speakers bureau for Biosense Webster, Boston Scientific and Medtronic and receives research grants from Biosense Webster, Boston Scientific, EP Dynamics and Spectrum Dynamics.