2017 ACVIM Forum Research Abstract Program

At drug administration AFR was 322 AE 30 fibrillations per minute (fpm) in the flecainide-treated horses and 299 AE 12 fpm in the control group (ns). Flecainide infusion was followed by significant (P < 0.05) AFR decrease that preceded restoration of sinus rhythm in all induced horses ( fig. 1A ). Time to cardioversion after flecainide infusion start was 4.3 AE 2.5 min. In the control animals, mean AF duration was 205 min (range 152-273 min) and no alteration in AFR was observed following saline administration. The last 30 min before spontaneous cardioversion, a gradual decrease in AFR was observed (P < 0.05) ( fig. 1B ). In the horse with spontaneous persistent AF, AFR decreased from 450 fpm to 300 fpm following flecainide administration without restoring sinus rhythm.