Postsurgical ventricular tachycardia in a horse.

This article discusses a case where a 2-year-old Thoroughbred racehorse developed ventricular tachycardia (an abnormally rapid heart rhythm) after undergoing a laryngoplasty and ventriculectomy with halothane anesthesia. The horse was successfully treated with an intravenous infusion of quinidine gluconate, but the exact cause of the arrhythmia could not be determined.

Case Description

• The racehorse underwent two operations – laryngoplasty (surgery to restore the function of the larynx) and ventriculectomy (surgical removal of a part of the stomach) under anesthesia maintained with halothane, a potent inhalational anesthetic.
• During surgery, the horse developed ventricular tachycardia, a condition where the lower chambers of the heart (ventricles) beat very quickly, leading to inefficient pumping of blood.
• The horse also exhibited other complications such as fever (febrile condition) and transient mild hypercarbia (abnormally elevated carbon dioxide (CO2) levels in the blood).

Treatment and Monitoring

• The horse was treated with an intravenous (IV) infusion of a medication called quinidine gluconate, known for its ability to help restore normal heart rhythms.
• To track the response to treatment and evaluate the horse’s cardiac rhythm, continuous electrocardiographic monitoring was used. Electrocardiography is a non-invasive procedure that records electrical activity of the heart over time.
• After 12 hours of IV infusion, conversion was achieved, indicating successful reversal of the ventricular tachycardia.

Outcome and Conclusion

• Despite successful treatment, the researchers were unable to determine the root cause that triggered the arrhythmia in the first place.
• This case illustrates the possible cardiac complications that can occur in horses following surgery and under general anesthesia. It also emphasizes the importance of continuous monitoring for early detection and management of such complications.