PVI is cornerstone of AF ablation. However, clinical outcome of only PVI in patients with persistent AF is insufficient due to AF substrate extending to left atrium. Strategy of catheter ablation for persistent AF is not established despite attempts of numerous left atrial substrate modifications. Additional PWI on PVI is one of expected effective strategies for persistent AF, because PW originated from common tissue of PV and is considered to play a part in AF trigger and maintenance. However, this strategy is also not established in the recent international consensus statement. Following two reasons are considered. One is the procedural difficulty in creating durable PWI, and another is the existence of patients who can recover by only PVI. The latest technology, ablation index, can create durable PVI, and may create durable PWI. Several reports suggested that PVI only strategy was sufficient in the patients with persistent AF who could maintain sinus rhythm after pharmacological or electrical cardioversion. Therefore, we planed this randomized clinical trial that compared between PVI alone and additional PWI on PVI using ablation index in the patients with persistent AF without pharmacological sinus rhythm conversion.