Propofol and medetomidine intravenous anaesthesia for transvenous electrical cardioversion in horses

Atrial fibrillation is a common tachyarrhythmia in racing horses associated with decreased performance. Transvenous electrical cardioversion is the preferred treatment for atrial fibrillation in those horses where medical therapy is either unsuccessful or unacceptable. Transvenous electrical cardioversion's main drawback is the necessity for general anaesthesia. This case series documents the details of three horses that were managed for sustained atrial fibrillation via transvenous electrical cardioversion procedures. In each case, the anaesthesia was maintained with the use of propofol and medetomidine intravenous infusions, which has not been previously reported for use in horses undergoing transvenous electrical cardioversion. Two of the horses were successfully converted without significant complications. One horse was unable to be converted after nine defibrillation attempts; however, anaesthesia was stable in all horses despite the concurrent use of antiarrhythmic drugs. No animal required inotropic support. Propofol-based protocols were safely utilised for three anaesthetics for transvenous electrical cardioversion with encouraging cardiovascular stability.