Variation in the frozen lesion size according to the non-occluded application duration and technique for cryoballoon ablation oleh Tetsuma Kawaji, Bingyuan Bao, Shun Hojo, Yuji Tezuka, Kenji Nakatsuma, Shintaro Matsuda, Masashi Kato, Takafumi Yokomatsu, Shinji Miki