Does using bipolar cautery eliminate the risk of electromagnetic interference (EMI) to a pacemaker (PM)?

Bipolar Cautery and Electromagnetic Interference with Pacemakers

While bipolar cautery significantly reduces the risk of electromagnetic interference (EMI) to pacemakers compared to unipolar cautery, it does not completely eliminate the risk. 1

Risk Reduction with Bipolar Cautery

• Bipolar cautery systems are preferred over unipolar systems as they are less hazardous for patients with pacemakers 1
• Bipolar cautery confines the electrical current between the two electrodes of the cautery device, significantly reducing the amount of current that can potentially interfere with pacemaker function 1
• The probability of adverse interactions has fallen dramatically due to improved pacemaker design and the almost universal use of bipolar leads, but EMI can still occur 1

Factors Affecting EMI Risk

The likelihood and potential clinical impact of EMI with pacemakers depends on several factors:

• Whether the patient is pacemaker-dependent 1
• Whether the pacemaker has unipolar or bipolar leads (bipolar leads provide better protection against EMI) 1
• Whether the cautery is bipolar or unipolar 1
• The relative distance from and orientation of the cautery relative to the pacemaker and leads 1
• The surgical site (interactions are more likely during chest or abdominal procedures) 1

Potential EMI Effects on Pacemakers

Even with bipolar cautery, the following adverse effects may still occur:

• Temporary or permanent resetting to a backup pacing mode 1
• Temporary or permanent inhibition of pacemaker output 1
• Increased pacing rate due to activation of the rate-responsive sensor 1
• ICD firing due to activation by electrical noise 1
• Myocardial injury at the lead tip that may cause failure to sense and/or capture 1

Research Evidence

• Studies have shown that closely spaced bipolar sensing (true bipolar) appropriately rejects electrocautery-induced EMI better than widely spaced sensing configurations 2
• In one study, none of the bipolar pacemakers tested experienced interference from electromagnetic fields, while unipolar configurations were more susceptible 3
• Another study found that modern device systems generally withstand periprocedural EMI exposure without malfunction, though inappropriate sensing can occur when unipolar electrocautery is used in close proximity (<8 cm) to the pacemaker generator 4

Recommendations for Perioperative Management

• For pacemaker-dependent patients, consider pre-operative reprogramming of the device to an asynchronous or triggered mode 1
• For non-pacemaker-dependent patients, ensure provisions for immediate activation of asynchronous pacing (via programmer or magnet) should inhibition occur 1
• Keep cautery use and power output to the minimum required 1
• Apply cautery in short bursts and not in close proximity to the device 1
• Monitor ECG and pulse oximetry during the procedure 1
• Interrogate the device after the procedure if cautery was used near the pacemaker or leads 1

Common Pitfalls to Avoid

• Assuming bipolar cautery eliminates all EMI risk can lead to inadequate monitoring during procedures 1
• Failing to identify pacemaker-dependent patients before surgery increases risk 1
• Using excessive power or prolonged bursts of cautery near the pacemaker system increases EMI risk 1
• Not having emergency equipment available for temporary pacing should pacemaker inhibition occur 1