Researchers at the University of California (UC), Davis are having success treating atrial fibrillation in horses through transvenous electrical cardioversion (TVEC).

Carrie J. Finno, DVM, DACVIM, an adjunct professor in large animal internal medicine at the UC Davis Veterinary Medical Teaching Hospital, writes of successfully using the procedure on Jody Carlson-Astrom's horse Massoun. In the most recent issue of the Center for Equine Health's The Horse Report, Finno discusses how TVEC was able to put Massoun's heart back into normal rhythm after he had reverted to an abnormal heart rhythm following the more conventional chemical treatment of quinidine sulfate.

With TVEC, two electrodes are inserted through catheters placed into the right jugular vein while the horse stands under sedation. One catheter is placed into the pulmonary artery and the other into the right atrium.

After the correct placement of the electrodes is confirmed, the horse is placed under general anesthesia and another confirmation is taken. The electrical shock is delivered directly to the heart by attaching the electrodes to a defibrillator unit. Timing the "shocks" by monitoring the cardiac cycle as seen by an electrocardiogram can put the heart back into the correct rhythm