In this patient with an implantable cardioverter-defibrillator (ICD) with planned shoulder surgery, her ICD should be reprogrammed immediately before the procedure to asynchronous pacing with disabling of tachycardia detection and shocking function.

In any patient with a cardiac implanted electronic device, three fundamental questions must be answered in order to appropriately determine perioperative device management. First, what type of device does the patient have (for example, pacemaker versus defibrillator)? Second, is the patient pacemaker dependent? Third, will the surgery be performed with instruments that result in electromagnetic interference in the vicinity of the device or its leads (for example, electrocautery)?

There is often confusion about pacemakers and defibrillators. An ICD is a pacemaker with extra capabilities (detection and treatment of a ventricular tachycardia or ventricular fibrillation). Management of the pacing and defibrillator functions may differ in specific clinical situations. For example, this patient can be considered pacemaker dependent given her history of complete heart block and atrioventricular sequential pacing on her electrocardiogram, requiring continued pacemaker function during surgery. However, her shoulder surgery will be in close proximity to her device and will increase the likelihood of electromagnetic interference that could alter both the pacing and defibrillator functions of her device. Therefore, in order to ensure adequate pacing and avoidance of shocks caused by electrical interference associated with instruments used during surgery, the device should be reprogrammed before the procedure.

Programming the device to asynchronous mode (DOO) will allow continued pacing of the atrium and ventricle but without the device sensing the cardiac response, thereby avoiding suppression of pacing due to electrical interference that the device might interpret as an elevated heart rate (that is, oversensing). Disabling the shock function will eliminate false detection of a tachyarrhythmia due to electrical interference. However, not all patients with pacemaker dependence require asynchronous pacing during surgery, and guidelines for device management before, during, and after surgery continue to evolve. Because of this, it is advisable to consult with the patient's outpatient electrophysiologist in advance of surgery.

Disabling the shock function of an ICD is possible by applying an external magnetic field to the device. The change in function associated with the application of a magnet to an ICD differs from doing so to a pacemaker. Magnet application induces asynchronous pacing (pacing regardless of what is sensed) in pacemakers, whereas magnet application in ICDs disables the shocking function of the device without changing pacing programming. In this patient, although disabling the shocking function is appropriate, doing so will not change the device to an asynchronous mode.

Devices often need to be interrogated after surgery; however, this option is incorrect because reprogramming is needed in this patient before she can proceed to surgery. In any patient whose device is reprogrammed before surgery, the device should be interrogated after surgery and confirmed to be “active.”

Advising against surgery is incorrect. Patients with implanted cardiac devices can safely undergo surgery provided the correct precautions are taken. Patients with acute arrhythmias may require stabilization, but in general, an implanted cardiac device in and of itself is not a contraindication to surgery or invasive procedures.

In summary, this patient is pacemaker dependent, has an ICD, and is having surgery in the vicinity of her device. Therefore, the patient's ICD requires reprogramming to an asynchronous mode, disabling of the tachytherapies, and appropriate device interrogation and reprogramming after the surgery.