Cardioversion of atrial fibrillation in a dog with structural heart disease using an esophageal-right atrial lead configuration

Atrial fibrillation is a common arrhythmia in dogs with structural cardiac disease and can result in significant clinical signs. Several methods of electrical cardioversion of atrial fibrillation have been described. Biphasic transthoracic cardioversion of atrial fibrillation in dogs with naturally occurring heart disease has been described in veterinary medicine and has been shown to be highly successful. In humans and research animals intracardiac and transesophageal cardioversion of atrial fibrillation has been described as an alternative to transthoracic cardioversion. While transesophageal cardioversion is very successful in humans and research animals, this technique has not been previously described in a clinical patient with naturally occurring heart disease in veterinary medicine. This report describes the use of transesophageal cardioversion in a dog with atrial fibrillation and structural cardiac disease. Cardioversion was unsuccessful using two electrodes positioned within the esophagus. Cardioversion of atrial fibrillation to normal sinus rhythm was successfully achieved and maintained using one electrode positioned within the esophagus and one electrode positioned within the right atrium using a synchronized monophasic shock of 50 J.