Electrosurgery and pacemakers

Electrosurgery and pacemakers

Electrosurgical equipment use radiofrequency energy in the range of 0.1 to 5 MHz. This can cause electromagnetic interference (EMI) with pacemakers and other cardiac implantable electronic devices (CIED). In general, if the use of cautery is below the umbilicus, with the indifferent electrode patch kept beneath the thighs, the chance of interference with a thoracic CIED is unlikely.

Electrosurgical equipment can have unipolar and bipolar modes of operation, the former being more frequently available. In unipolar mode, the current flows from the cautery tip to the indifferent electrode kept behind the body. In bipolar mode, the current flows between two electrodes at the tip of the cautery probe. Bipolar mode is safer in the presence of a pacemaker, less likely to cause EMI. Maximum chance of EMI is when the cautery is used within 8 cm of the CIED.

If there is interference noted with the device during the procedure like inhibition of a pacemaker, using cautery in short bursts will be useful to prevent life threatening asystole. Another option is to reposition the ground electrode of the electrosurgical equipment to redirect the current path away from the implanted device.

Pacemakers are programmed to asynchronous mode and ICD (implantable cardioverter-defibrillator) tachyarrhythmia therapies are suspended prior to surgery if interference is likely.

If the patient is not pacemaker dependent, pacemaker can be programmed to a low back up pacing rate in addition. CIED programming is done before and after the surgical procedure to ensure proper functioning of the device. If device programmer is not available in an emergency, taping a magnet over the device will suspend ICD shocks and switch the pacemaker to asynchronous mode. Magnet can be removed after the surgery to resume normal function.