What is a case example of the risks of incomplete preoperative evaluation on the perioperative management of permanent pacemakers (PPMs) and automatic implantable cardioverter-defibrillators (AICDs)?

Updated: Oct 29, 2018
  • Author: Albert H Tsai, MD; Chief Editor: Sheela Pai Cole, MD  more...
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A 57-year-old female patient with a past medical history of sick sinus syndrome, dilated cardiomyopathy with a left ventricular ejection fraction (LVEF) of 30%, and VF who has undergone AICD implantation presents for emergency open cholecystectomy to treat gallbladder rupture. Because the case is an emergency, preoperative evaluation is limited. Before induction, a V-paced rhythm at 75 beats/min is noted on telemetry. After uneventful induction, intubation, and arterial line placement, a magnet is applied to the AICD to deactivate antitachycardic therapy.

As the surgeon makes an incision with the electrocautery, you notice a decrease in HR from 75 beats/min to 44 beats/min, a loss of pacing spikes on telemetry, and a decrease in BP from 110/67 mm Hg to 85/48 mm Hg. You immediately instruct the surgeon to stop use of the electrocautery, whereupon you notice a return of a V-paced rhythm at 75 beats/min and an increase in BP to 105/75 mm Hg.

Electrophysiology consultation is obtained to reprogram the AICD to asynchronous pacing; however, in view of the emergency nature of the case, the surgeon wishes to proceed with the operation. After the surgeon switches to a bipolar cautery, you allow resumption of the procedure, and the electrophysiologist arrives 30 minutes later to reprogram the device to VOO at 75 beats/min.

Approximately 1 hour later, as the surgeon continues surgical excision of the gallbladder, the patient suddenly goes into VF with loss of arterial waveform. You initiate ACLS protocol with chest compressions and administration of epinephrine and amiodarone; however, defibrillation is delayed, because defibrillator pads were not applied before the patient was positioned and paddles were not readily available.


This scenario, though similar in appearance to that outlined in case example 1, differs in one crucial respect, which emphasizes the importance of differentiating a PPM from an AICD.

Even though a thorough preoperative evaluation was not possible, owing to the surgical emergency, the history of sick sinus syndrome and the appearance of a paced rhythm on telemetry should indicate to the practitioner that the patient is probably pacer-dependent. Therefore, whereas application of the magnet will appropriately deactivate the AICD's defibrillation function and thus prevent inappropriate shocking, it will have no effect on the device's pacemaker function and thus will not prevent inappropriate sensing.

As in case example 1, inappropriate sensing related to electrocauterization resulted in inadequate cardiac output as the patient’s underlying sinus bradycardia was unmasked. Internal reprogramming of the device to asynchronous pacing is the appropriate intervention, along with resumption of the emergency surgical procedure while reprogramming is awaited, on the assumption that steps are taken to reduce EMI (eg, use of a bipolar cautery and minimizing current amplitude).

The failure to defibrillate the patient promptly after she experiences VF highlights the necessity of having alternative antitachycardic therapy immediately available in a patient with history of ventricular dysrhythmias and a deactivated AICD. Defibrillator pads should have been applied to the patient before the AICD was deactivated; this would have allowed transcutaneous pacing as well as immediate defibrillation. As in case example 1, it is vital to perform postoperative reinterrogation to ensure the return of antitachycardic therapy after magnet removal and reprogramming to synchronous pacing.

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