Objective Atrial fibrillation is the most common arrhythmia in clinic, and more than 90% of foci are located within pulmonary veins. The mechanism of atrial fibrillation is not clear, and autonomic nerves system maybe involves it. This study set up a animal model of paroxysmal atrial fibrillation and investigate effect of left vagal stimulation and autonomic nerve blockade on the electrophysiological properties of the pulmonary veins, which would show how the autonomic nerve blockade contribute to atrial fi...