Implantable pacemakers and defibrillators: implications for anesthesia and perioperative management

The technological complexity of implantable devices for managing arrhythmias, specifically pacemakers and defibrillators, has increased spectacularly since their introduction a few decades ago. A growing number of patients with these devices are undergoing surgery and it is therefore essential to understand how they work and what the real associated risks are. Manuals and reference works on anesthesia may provide little information on these devices and their perioperative management. It is no longer satisfactory to place a magnet over these devices during surgery and assume that this action will protect the patient from the possible effects of electromagnetic interference. This review examines the basic principles and operation of implantable pacemakers and defibrillators, the relevant nomenclature, and the sources and effects of electromagnetic interference; the current recommendations for the perioperative management of patients fitted with these devices are also discussed.