A 65-year-old man was referred for the evaluation of operability from the neuro-surgical department. They found an abnormal change of electrocardiogram (ECG) on the ECG monitoring. The patient had been underwent the implantation of permanent pacemaker (DDD type) with the diagnosis of sick sinus syndrome at another hospital 3 months ago. The patient didn't have any symptom. The ECG showed 3 different morphology of QRS which were intrinsic beat, fusion beat, and pacing beat. After modifying the AV delay from 200 ms to 250 ms, sinus rhythm was only documented on ECG without fusion or pacing beats.