A 67-year-old man with peripheral vascular disease is about to undergo transmetatarsal amputation and lower extremity skin grafting. The patient had a recent diagnosis of ischemic cardiomyopathy (LVEF 25%) and a latest generation implantable cardioverter defibrillator (ICD) placed a few months ago. The patient is pacemaker dependent 99% of the time according to the recent outpatient ICD interrogation. The surgeon is urging you to quickly bring the patient into the operating room, not worry about the ICD, and promises to avoid any electrocautery.
Which of the following statements is MOST correct?
A. Applying a magnet for the duration of the case or obtaining an EP consultation before the case is the standard of care for all surgical patientsCorrect Answer: B
The 2011 Heart Rhythm Society/American Society of Anesthesiologists expert consensus statement notes that a single recommendation for all patients with cardiovascular implantable electronic devices (CIEDs) is not appropriate. It further states that in some circumstances, remote or perioperative CIED interrogation or reprogramming (including changing pacing to an asynchronous mode and/or inactivating ICD tachytherapies), application of a magnet over the CIED with or without postoperative CIED interrogation or use of no perioperative CIED interrogation or intervention may be necessary. This decision should be made depending on the nature and location of the operative procedure, likelihood of use of monopolar electrocautery, type of CIEDs (ie, pacemaker vs ICD), and dependence of the patient on cardiac pacing. It is further recommended to inactivate the ICD for all surgeries above the umbilicus implying that it was unnecessary to do so for surgeries below the umbilicus. It was argued that the risk of electromagnetic interference being detected, and hence of discharge of the device, was very low. It will take 3 to 4 seconds to detect the ventricular fibrillation and another 5 to 10 seconds for the ICD to charge before the shock can be delivered.
Application of a magnet in patients with ICD, who are not pacemakerdependent and are undergoing infraumbilical surgery, is thus not universally necessary. Application of a magnet will generally deactivate both modes, antitachycardic pacing and defibrillation, even though some ICD models (Boston Scientific and St. Jude Medical) can be programmed to ignore the magnet. If the magnet deactivates both modes on magnet application, removal of the magnet generally reactivates both modes. Applying a magnet onto an ICD will not affect the pacemaker function of the ICD. This is distinctly different when compared with the application of a magnet onto a simple pacemaker, which generally switches the pacemaker into an asynchronous mode (DOO, VOO). Harmonic scalpel and bipolar electrocautery as opposed to monopolar electrocautery confer minimal risk of electromagnetic interference.
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