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Recommendations for preventing and managing interference in patients with implanted cardiac devices


Recommendations on the prevention and management of interference caused by medical procedures in patients with implanted electronic cardiac devices are published today in EP Europace, a journal of the European Society of Cardiology (ESC) and presented at EHRA 2022, a scientific congress of the ESC.

Interference is often caused by many medical procedures, but rare consequences are largely preventable if preventive actions are taken. The document outlines what medical personnel should do before and during different types of medical procedures. Patients can also contribute by carrying their device card which specifies the type, model and manufacturer.”

Professor Markus Stühlinger, lead author, Medical University of Innsbruck, Austria

The article covers pacemakers, which keep the heart beating steadily and not too slowly; defibrillators, which stop life-threatening heart rhythms by delivering a shock; and loop recorders, used to detect and diagnose arrhythmias.

Interference that may affect the operation of these devices may occur during medical procedures due to electromagnetic fields (eg during surgery), magnetic field (eg magnetic resonance imaging; MRI ), radiation (eg, cancer treatment) or acoustic waves (eg, lithotripsy to destroy kidney stones). The result is that the electronic heart device may cease to function temporarily or permanently, or deliver an unnecessary shock.

Modern surgery typically uses electrocoagulation, where an electric current is delivered through a scalpel. “If the procedure is close to the generator of a pacemaker or defibrillator, the device may recognize the signal and respond to it inappropriately,” Prof. Stühlinger explained. “This can lead to pacing inhibition, leading to a drop in heart rate or unnecessary shock as the device mistakenly detects a dangerous arrhythmia.”

The authors describe the measures to be taken to avoid any malfunction of the device due to interference. For surgery, the first step is to check how dependent the patient is on the device – for example, does he need constant stimulation or not? In addition, medical personnel should verify that the device and its battery are working properly. The second step is to test how the device reacts to having a magnet placed next to it. If the device responds as expected, surgery can proceed normally and ECG and pulse should be monitored. If the behavior of the device is abnormal, a magnet can be placed near the device during surgery to prevent interference from electrocautery.

It is estimated that 50% to 75% of patients with implanted cardiac devices will require an MRI during the life of their device. The document states that MRI should only be performed on patients with these devices in centers with appropriate teams, protocols and equipment. “Collaborative relationships between radiologists, physicists, cardiologists, and allied health personnel are essential for safe outcomes,” the authors state. They recommend reprogramming the cardiac device before and after a scan and provide step-by-step instructions.

For radiation therapy, there is a small risk that heart devices will not work properly after treatment. Professor Stühlinger said: “Implanted pacemakers and defibrillators should be checked regularly during radiotherapy, either with remote monitoring or with a weekly in-person appointment.

He concluded, “This is a comprehensive report outlining the preventative measures that should be employed to ensure that patients with implanted heart devices can safely undergo medical procedures.

The international consensus statement was developed by the European Heart Rhythm Association (EHRA), an arm of the ESC; the Heart Rhythm Society (HRS); the Asia Pacific Heart Rhythm Society (APHRS); and the Latin American Heart Rhythm Society (LAHRS). It is also published in Heartbeatthe official journal of the SRH, Arrhythmia Diarythe official journal of APHRS, and Journal of Interventional Cardiac Electrophysiologythe official journal of the LAHRS.


European Society of Cardiology