Effect of induced chronic atrial fibrillation on exercise performance in Standardbred trotters.

Background: Atrial fibrillation (AF) is the most common arrhythmia affecting performance in horses. However, no previous studies have quantified the performance reduction in horses suffering from AF.

Objectives: To quantify the effect of AF on maximum velocity (V ), maximum heart rate (HR ), heart rate recovery (T ), hematologic parameters and development of abnormal QRS complexes.