Transvenous electrical cardioversion of equine atrial fibrillation: technical considerations.
Authors: McGurrin M Kimberly J, Physick-Sheard Peter W, Kenney Daniel G, Kerr Carolyn, Hanna W J Brad
Journal: Journal of veterinary internal medicine
Summary
# Transvenous Electrical Cardioversion for Equine Atrial Fibrillation Quinidine has long been the mainstay of pharmacological treatment for equine atrial fibrillation, yet a significant proportion of horses experience adverse effects or fail to respond adequately, creating a clinical need for alternative approaches. McGurrin and colleagues developed and refined a transvenous electrical cardioversion (TVEC) technique using biphasic, truncated exponential shock waves delivered via catheter-integrated electrodes positioned in the right atrium and pulmonary artery, evaluating both safety and efficacy across cadaveric and live animals in chronic AF. Working through incremental energy delivery up to 300 joules under general anaesthesia, the team achieved successful cardioversion in seven of eight client-owned horses without requiring concurrent antiarrhythmic medication, with no adverse responses to appropriately delivered shocks observed in any animal. Catheter placement guided by combined ultrasonography and pressure monitoring proved critical to procedural success, and postmortem examination revealed no tissue damage from the electrical intervention. For practitioners managing AF cases refractory to or intolerant of pharmacological therapy, TVEC represents a viable interventional alternative, though the technique requires specialist equipment, general anaesthesia, and careful technical execution—factors that will influence its practical availability in most equine practices.
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Practical Takeaways
- •TVEC is a viable alternative treatment for equine atrial fibrillation in cases where horses cannot tolerate or do not respond to quinidine therapy
- •The procedure requires right jugular vein catheterization under general anesthesia with imaging-guided electrode placement—collaborate closely with your referral center's cardiology team
- •No additional antiarrhythmic medications are needed during the procedure, reducing medication-related adverse effects seen with conventional treatment
Key Findings
- •Transvenous electrical cardioversion (TVEC) achieved cardioversion in 7 of 8 client-owned horses with chronic atrial fibrillation
- •Combined ultrasonography and pressure guidance proved most effective for appropriate catheter electrode placement in the right atrium and pulmonary artery
- •No adverse effects were observed from cardioversion attempts, general anesthesia, or appropriately delivered biphasic truncated exponential shocks up to 300 J
- •TVEC offers a safe, effective alternative to quinidine salts for horses unable to tolerate pharmacologic cardioversion