Electroanatomic mapping in atrioventricular junction ablation during sinus rhythm for tachycardia-bradycardia syndrome with persistent left superior vena cava.

This is the first report describing atrioventricular junction ablation during sinus rhythm in a patient with persistent left superior vena cava. Electroanatomic mapping systems and awareness of anatomic and electrogram variations may decrease procedure time, decrease fluoroscopy time, and minimize delivery of ineffective ablation lesions.