Implantable pacemakers and defibrillators (ICDs) are life-saving technologies increasingly encountered by EMS providers in the field. As the prevalence of cardiac rhythm management devices grows, so does the importance of understanding how they function—and how they can impact prehospital care. This lecture offers an introduction to pacemakers and ICDs tailored specifically for EMS professionals. Attendees will gain a foundational understanding of the indications, functionality, and types of implantable cardiac devices. The session will cover device identification, common rhythms associated with device therapy, and appropriate EMS responses to device-related emergencies such as failure to pace, inappropriate shocks, or pacemaker-mediated tachycardia. Additionally, the lecture will introduce conduction system pacing (CSP)—a new frontier in device therapy that includes His-bundle and left bundle branch pacing. EMS providers will learn how these novel approaches differ from traditional pacing, what implications they may have on ECG presentation By the end of this session, EMS providers will be better equipped to recognize, assess, and manage patients with implantable devices, enhancing both patient safety and provider confidence in the field. Whether you’re a new EMT or a seasoned paramedic, this lecture will demystify “the box in the chest” or "capsules in the heart" and empower you with actionable knowledge.