Cardiac implantable electronic devices (CIEDs)—a category encompassing permanent pacemakers, implantable cardioverter-defibrillators, cardiac resynchronization therapy devices, and newer leadless or subcutaneous systems —are increasingly encountered in patients undergoing cardiac surgery. Advances in device therapy over recent decades have improved survival and quality of life for patients with bradyarrhythmias and tachyarrhythmias, meaning more surgical candidates now have these implants. Effective perioperative management of CIEDs is critical: interference with device function or inappropriate device behavior during surgery can lead to severe hemodynamic consequences, including bradycardia/asystole or malignant arrhythmias. In the context of adult cardiac surgery, where electromagnetic interference from surgical equipment is common and procedures often involve the heart directly, careful planning and multidisciplinary coordination are essential to ensure patient safety and optimal device function. Anesthesiologists, surgeons, and cardiology/electrophysiology specialists must work together to anticipate device interactions and implement strategies to prevent intraoperative CIED malfunctions while maintaining necessary pacing and defibrillation support.