Ali Reza Taghavi Razavizadeh - Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
Mohammad Reza Aslani - Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Shahrekord, Iran

Atrial fibrillation (AF) was detected as an incidental finding in a 14 years old brood mare horse which was maintained for student education in the teaching hospital, Faculty of Veterinary Medicine, Mashhad. Irregular heart rhythm, variable intensity of heart sounds and f waves were revealed in clinical examination and electrocardiography. Hematology showed normal values and hyponutremia was observed in serum biochemical analysis. Treatment of the horse was done with oral administration of quinidine sulfate (200 mg tabs). Normal rhythm was appeared after 24 hours of treatment. Herein, we have discussed the etiology and the treatment procedure of this dysrhythmia

Atrial fibrillation, Quinidine sulfate, Electrocardiogram, Biochemical factors Horse