Pharmacological Treatment for Atrial Fibrillation —Modalities in Equines and Companion Animals

Cardiac arrhythmias are probably more common in horses than in any other domestic animal species where poor performance and exercise intolerance is the most frequent clinical complaint. Atrial fibrillation is a type of cardiac arrhythmia that appears as a common finding during medical examinations in humans, large breed dogs and horses. Clinical presentations are of a particular value in racehorses in high performing activities. Atrial fibrillation is characterized by an irregular heart rhythm, secondary to a primary disease or without any sign of comorbidity. The generation and maintenance of Atrial Fibrillation requires a substrate. Some breeds have a genetic predisposition to developing Atrial Fibrillation. Most cases of Atrial Fibrillation are of the paroxysmal type and self-regulate within a few hours to days without the need for treatment. The focus of this study is on the arrhythmic agents that are used for the treatment of Atrial Fibrillation, therefore other arrhythmic agents may not be included, or are included to demonstrate their effect on increasing, inhibiting or decreasing efficacy when used together with medications for the treatment of Atrial Fibrillation. The “working horse” for the pharmacological treatment of Atrial Fibrillation is Quinidine.