Automatic internal cardiac defibrillator

Internal cardiac defibrillators (ICDs) are used in populations that are at high risk of sudden death from cardiac tachydysrhythmias.

Internal cardiac defibrillators consist of two defibrillating electrodes or patches and separate electrodes that are used for pacing and sensing. The patches are placed near the pericardium. The generator is implanted in either the abdomen or chest wall.

All ICDs are extremely sensitive to EMI used in electrocautery. EMI is detected as ventricular fibrillation by the device and delivers a shock to the patient. Magnet application will cause the device to suspend detection, but it will not interfere with the pacing function. Intraoperatively, if ventricular fibrillation occurs, the magnet can simply be removed, and the device can deliver a shock, usually within 10 seconds. External defibrillators should always be readily available in case of failure.

The ICD can be turned off manually for the duration of the operation before the patient is taken into the operating room, and it can be turned back on in the postanesthesia care unit. Personnel trained in the use of an external cardiac defibrillator should be readily available while the device is turned off.

If only bipolar cautery is used, the device can usually remain on.