Proximity of the vagus nerve to a patent ductus arteriosus (PDA) can cause traction or entrapment of vagus nerve during surgical closure of the in rare occasions. This can lead to a life threatening postoperative bradycardia. Herein, we report a case of bradycardia caused by unexpected irritation of the vagal trunk by the end of operation. The patient was managed by re-opening the chest, lung retraction and removal of mediastinal pleura sutures. The vagal trunk entrapped in the suture line was released immediately. Heart rate accelerated and hemodynamic restored after a short period of observation. The operation terminated as routine, patient extubated in OR and discharged within 24 hours with no further complication. This irritation of vagus results in vagal bradycardia during or by the end of operation. Awareness of a surgeon of this issue can minimize the risks and complications of the open closure of PDA.