When a patient has a pacemaker and requires operation, surgeons have to consider some possible intraoperative pacemaker complications induced by electrocautery. Electrocautery is commonly used during surgery to achieve hemostasis. However, this very effective tool may introduce innumerable problems in the paced patient, including irreversible damage to the pulse generator, pacemaker reprogramming, induction of a rise in the capture threshold, and ventricular fibrillation. Although electrocautery may be avoided in some surgical procedures, open heart surgery cannot be performed without it. One case is presented to illustrate how to achieve hemostasis while decreasing electric interference and how to protect the permanent pacemaker while avoiding those possible complications during the defibrillation. The purpose of this article is to call attention to potential problems induced by electrocautery and in an effect to facilitate the perioperative management of the paced patient undergoing open heart surgery.