Catheter placement on fluoroscopy during internal electrical cardioversion. Anteroposterior view shows a quadripolar catheter at the right ventricular apex, a 7 + 7-polar catheter in the distal coronary sinus and along the lateral wall of the right atrium, and decapolar ring catheters in the left superior pulmonary vein, left inferior pulmonary vein, and right superior pulmonary vein.