NPPA and atrial fibrillation: The aims of our prospective study were: (1) to evaluate whether preoperative ANP level might have a predictive value for the success rate of epicardial HIFU ablation (2) to estimate the recovery of atrial mechanical function following epicardial HIFU ablation and their impact on alteration of endocrine secretion in 6 moths follow-up (3) to analyze the effect of epicardial HIFU ablation of concomitant AF on atrial endocrine secretion based on serial postoperative ANP levels.