Treatment of atrial fibrillation in three racehorses.

The research study deals with the treatment of atrial fibrillation in three young Standardbred racehorses using quinidine sulphate administered directly into the stomach. The study concludes that, based on the positive outcome and the horses’ return to normal heart rhythm post-treatment, atrial fibrillation in horses may not necessarily be tied to detectable pathological heart changes.

Research Methodology and Treatment

• The researchers focused on three young Standardbred pacers diagnosed with atrial fibrillation.
• These horses were treated using quinidine sulphate (QS), a medication known for treating atrial fibrillation in humans and other animals, and that possesses cardioversion properties (ability to restore normal heart rhythm).
• The administered method of drug delivery was through a stomach tube, bypassing the horses’ oral intake mechanism.
• The dosage of QS provided to the horses was 10 grams, given every 2 hours until cardioversion, the process of restoring the heart to a normal rhythm, was achieved. The total consumed dose varied between 20 and 30 grams per horse.

Post-treatment Procedure and Findings

• After the treatment, the horses were not given any additional medication or follow-up treatments. They were allowed a rest period of 3 months.
• During the rest period, the horses’ cardiac status was monitored through electrocardiograms at the 3-month stage and again at the 6-month stage. Both times, the electrocardiograms indicated that the horses had returned to a normal sinus rhythm.
• Additionally, all three horses went on to win races post-cardioversion, an indication of their full physical recovery and return to peak performance levels.

Interpretation and Deductions

• The researchers concluded that atrial fibrillation in horses may not be attributable to detectable pathological changes in their hearts. This is based on the facts that 1) the horses returned to normal function after cardioversion, 2) there was no observable deterioration in cardiac performance post-cardioversion, and 3) they were able to perform to the extent of winning races post-treatment.
• The study suggests that QS may be an effective treatment for atrial fibrillation in horses, however, a larger sample size and stricter follow-up procedures could help provide more concrete supporting evidence.