Large animals as models of atrial fibrillation.

In clinical practice, atrial fibrillation (AF) is the most common cardiac arrhythmia in humans and it may lead to numerous complications, including central nervous system embolism. The electrical activity of the heart in AF is rapid and chaotic, while the atrioventricular conduction leads to irregular ventricular contraction. Consequently, the stroke volume is reduced, which may lead to symptoms of heart failure. Heart failure is one of the causes of AF as well. Numerous in vivo and in vitro models are used to study the pathophysiology of AF. Animal models play a key role in understanding the mechanisms of arrhythmias as well as in developing treatment regimens. The models of AF include large animals (goats, sheep, pigs, dogs) as well as small laboratory animals. This study reviews the large animal models of AF, which enhance our understanding of numerous mechanisms responsible for the development of AF, but we must be aware that the pathomechanism of AF in humans is complex and is affected by numerous factors, including environmental and congenital ones.