How is the patient with an AICD managed in the perioperative period?
There are two major concerns with the patient present-ing for surgery who has an AICD implanted. First, the reason why the patient had the device implanted should be thoroughly evaluated and anesthetic management planned accordingly. For example, patients with severe left ventric-ular dysfunction require more intensive monitoring and altered anesthetic technique. Second, factors that may interfere with proper function of the device must be antic-ipated and measures taken to prevent malfunction. In the perioperative period, the most likely source of interference with AICD function stems from high-frequency electro-magnetic signals caused by surgical electrocautery. The AICD software may interpret these signals as ventricular fibrillation or tachycardia and the AICD device may respond with inappropriate shock delivery or antitachy-cardia pacing. This, in turn, could potentially cause severe dysrhythmias. Therefore, the current recommendation for patients with an AICD undergoing elective surgery is to reprogram the device prior to surgery in order to deacti-vate dysrhythmia-sensing and defibrillator functions, and to set the pacemaker function to an asynchronous mode if possible. Preoperative assessment should include determining the details of the manufacturer, the model, the programmed settings, and when the device was last checked for proper function and battery charge. Once the device is deactivated, an external defibrillator must be readily available at any time and external defibrillator pads may be placed on the patient. In emergency cases only, a magnet can be placed over the device to deactivate the dysrhythmia detection and defibrillator functions of the AICD. Various models and manufacturers might differ in details as to how the pacing mode or the defibrillator mode is altered when a magnet is placed over the device or after the magnet has been removed. After any procedure, elective or emergency, the proper function of the AICD device has to be evaluated by qualified personnel.