Management and complications of anesthesia for transvenous electrical cardioversion of atrial fibrillation in horses: 62 cases (2002-2006).

This study investigates how anesthesia was managed during a procedure called transvenous electrical cardioversion (TVEC), used to treat atrial fibrillation in horses. It also provides details about any complications that occurred during these procedures. The data from horses undergoing this procedure was compared to those of another group of horses that were being anesthetized for magnetic resonance imaging (MRI).

Methods and Participants

• This is a retrospective case study where the researchers reviewed medical records from various cases. Those who participated included 62 horses with atrial fibrillation with no underlying heart disease and 60 horses with no atrial fibrillation. The first group went through the TVEC procedure while the second group was undergoing MRI.
• Details such as patient signalment, weight, duration of anesthesia, heart rate and arterial blood pressure during anesthesia, anesthetic drugs administered, method of ventilation, complications around the time of the operation, and the quality of recovery were collected and noted from the medical records.

Findings and Results

• The data showed that the horses in the TVEC group were primarily Standardbreds and over a year old. These horses went through 76 episodes of anesthesia.
• For more than half of the anesthetic incidents, only xylazine was used as a pre-medication. In about one third of the cases, both xylazine and butorphanol were used. Ketamine, often in combination with diazepam and guaifenesin, served as the induction drug in almost all the anesthesia episodes.
• Bradycardia, or rather slow heart rate, was observed in about one fifth of the anesthesia episodes.
• There were minor signs of possible postanesthetic myopathy, a muscular disease usually characterized by muscle inflammation and weakness, in almost 8% of the anesthetic occurrences.
• When the TVEC group was compared to the MRI group, no significant differences were noticed in terms of the occurrence of bradycardia and the use of inotropic drugs, which increase the contractility of the heart.

Conclusion

• The researchers conclude that short-duration anesthesia for TVEC of atrial fibrillation in horses with no underlying heart disease is relatively safe. This integral piece of information serves as a valuable contribution to veterinary anesthesia, especially when treating horses with atrial fibrillation.