Electromagnetic Interference with Implantable Cardioverter Defibrillators at Power Frequency: An in vivo Study
Background—The number of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac death is continuously increasing. Given the technological complexity of ICDs it is of critical importance to identify and control possible harmful electromagnetic interferences (EMI) between various sources of electromagnetic fields (EMFs) and ICDs in daily life and occupational environments.
Methods and Results—Interference thresholds of 110 ICD-patients (1-,2-,3-chamber ICD's) were evaluated in a specifically developed test site. Patients were exposed to single and combined electric and magnetic 50Hz fields with strengths of up to 30kVm-1 and 2.55mT. Tests were conducted considering worst-case conditions including maximum sensitivity of the device or full inspiration. With devices being programmed to nominal sensitivity, ICDs remained unaffected in 91 (83%) patients. 5 of 110 (5%) devices showed transient loss of accurate right ventricular (RV) sensing, while 14 of 31 (45%) of the 2- and 3-chamber devices displayed impaired right atrial (RA) sensing. No interference was detected in 71 (65%) patients within the tested limits with programming to maximum sensitivity, while 20 of 110 (18%) subjects exhibited RV-disturbances and 19 of 31 (61%) subjects RA-disturbances.
Conclusions—Extremely low frequency daily life EMFs do not disturb sensing capabilities of ICDs. However, strong 50Hz EMF, present in certain occupational environments, may cause inappropriate sensing potentially leading to false detection of atrial/ventricular arrhythmic events. When comparing the RA/RV interferences the atrial lead is more susceptible to EMF.
- Electromagnetic interference (EMI)
- power frequency (50/60 Hz)
- limit values
- implanted cardioverter defibrillator
- Received April 7, 2013.
- Revision received October 2, 2013.
- Accepted October 10, 2013.