Pacemakers and ICDs in the operating room
Stem
A 74-year-old man, 78 kg, is scheduled for open sigmoid colectomy through a midline incision. He has ischemic cardiomyopathy with an ejection fraction of 30% and complete heart block, and has a biventricular ICD in the left chest. His ECG shows 100% paced complexes at 70. The device was last checked 9 months ago, and he has had no shocks.
Question
How will you manage his device before, during and after surgery?
Ideal answer
HeadlinePacemaker-dependent with an ICD: monopolar cautery above the umbilicus can inhibit pacing into asystole or trigger an inappropriate shock.1 I get the device team in.
- Identify the device and settings; interrogate; get a prescription, because an ICD should be checked within 6 months and his is 9 months out.1
- Reprogram to asynchronous pacing, tachytherapy suspended, at a rate that covers his needs; a magnet on an ICD turns off shocks but has no effect on pacing.1
- External defibrillation and pacing pads before induction, with a plethysmograph or arterial line so I see perfusion when cautery obscures the ECG.
- Surgeon: dispersive pad placed so current avoids the generator, bipolar or ultrasonic instruments where possible, short bursts.2
- Continuous monitoring with pads until reprogrammed and interrogated, restoring his original settings after surgery.2
Breaking down the answer
- Dependence decides the plan — if EMI inhibits pacing in a dependent patient, the result is severe bradycardia or asystole.2 An underlying rhythm on a pacing check or a history of heart block answers the question.
- Above versus below the umbilicus — below, with a correctly placed pad, there is minimal need to reprogram or use a magnet; above, clinically important EMI occurred in 20% of noncardiac cases in one study.1
- Magnet behavior is device-specific — on most pacemakers a magnet gives asynchronous pacing at a set rate that may not meet his needs, and must be confirmed for the device.2 The 2020 ASA advisory discourages indiscriminate magnet use.1
- Distance — cautery within about 6 inches of the generator is the highest risk for inhibition or inappropriate therapy.1
- Rate-responsive features off — minute-ventilation sensors misread ventilation and EMI as exercise and pace fast; the device team disables them.
- Re-interrogation triggers — cardioversion, defibrillation, large blood loss or electrolyte shifts.2 The plan has an end point, not just a start.
Follow-up question
Two hours into the case, with the ICD therapies suspended, the monitor shows ventricular fibrillation and the arterial trace goes flat.
What do you do?
Follow-up answer
HeadlineVentricular fibrillation the suspended ICD cannot treat. I call it out, stop cautery, call for help and the code cart.
The pads are already on, so I defibrillate immediately with the external defibrillator and run CPR and ACLS between shocks. Had a magnet suspended therapy, I would remove it and watch briefly for the ICD to treat, without delaying an external shock.1 After return of circulation, the cause: ischemia, potassium, magnesium, acidosis. I tell the device team, because the device needs interrogation after an external shock, and he stays monitored with pads until his settings are restored.2
Pitfalls that cost points
- Putting a magnet on an ICD and assuming the patient is now safely paced.
- Leaving recovery with tachytherapy still off.
Rapid-fire
Q: How often should a pacemaker and an ICD be checked? A: Pacemakers yearly; ICDs and CRT devices every 6 months.1
Q: How should a leadless pacemaker be managed when EMI is expected? A: Reprogram it to VOO asynchronous pacing.1
Q: How do you confirm a magnet is working on a subcutaneous ICD? A: Listen for the audible beep; if absent, reposition it or reprogram.1
Q: What does the fourth letter of the pacemaker code describe? A: Rate modulation, the ability to change rate to meet physiologic demand.2
Q: How much battery life should the device have? A: At least 3 months.2
Numbers to know
| Item | Value |
|---|---|
| Pacemaker interrogation | Yearly1 |
| ICD or CRT interrogation | Every 6 months1 |
| EMI above umbilicus | Clinically important in 20%1 |
| High-risk cautery distance | Within 6 inches of generator1 |
| Minimum battery life | 3 months2 |
Links
- Heart failure and reduced ejection fraction, Preoperative cardiac evaluation for non-cardiac surgery, ACLS adapted to the operating room, Intraoperative cardiac arrest: care after return of circulation
- Atlas: Monitor atlas: perioperative cardiac events
- 2020 ASA practice advisory for CIEDs; 2011 HRS/ASA expert consensus statement
Sources
- 1.Change of Pace: An Update on the Perioperative Management of Cardiovascular Implantable Electronic Devices (CIEDs) · APSF · apsf.orgSummarizes the 2011 HRS/ASA expert consensus and the 2020 ASA practice advisory (Anesthesiology 2020;132:225-252), whose full text was not reachable from the fetcher.
- 2.Cardiac implantable electronic devices: pacemakers · OpenAnesthesia · openanesthesia.orgStates the ASA advisory recommends interrogation 3-6 months before surgery; the APSF summary of the HRS/ASA consensus gives yearly for pacemakers and 6 months for ICD/CRT. The page uses the HRS/ASA intervals.
Facts on this page were checked against these sources on Oct 15, 2026. Guidelines change; confirm doses against current institutional protocols.