Exposure to strong 50-Hz electromagnetic fields caused right ventricular sensing disturbances in 5% and right atrial disturbances in 45% of ICD patients at nominal sensitivity.
Observational (n=110)
Does exposure to strong 50-Hz electromagnetic fields cause sensing disturbances in patients with ICDs?
Strong 50-Hz electromagnetic fields found in occupational environments can cause inappropriate sensing in ICDs, particularly affecting the atrial lead.
BACKGROUND: The number of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac death is continuing to increase. Given the technological complexity of ICDs, it is of critical importance to identify and control possible harmful electromagnetic interferences between various sources of electromagnetic fields and ICDs in daily life and occupational environments. METHODS AND RESULTS: Interference thresholds of 110 ICD patients (1-, 2-, and 3-chamber ICDs) were evaluated in a specifically developed test site. Patients were exposed to single and combined electric and magnetic 50-Hz fields with strengths of up to 30 kV·m⁻¹ and 2.55 mT. 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 patients (83%). Five of 110 devices (5%) showed transient loss of accurate right ventricular sensing, whereas 14 of 31 (45%) of the 2- and 3-chamber devices displayed impaired right atrial sensing. No interference was detected in 71 patients (65%) within the tested limits with programming to maximum sensitivity, whereas 20 of 110 subjects (18%) exhibited right ventricular disturbances and 19 of 31 (61%) subjects exhibited right atrial disturbances. CONCLUSIONS: Extremely low-frequency daily-life electromagnetic fields do not disturb sensing capabilities of ICDs. However, strong 50-Hz electromagnetic fields, present in certain occupational environments, may cause inappropriate sensing, potentially leading to false detection of atrial/ventricular arrhythmic events. When the right atrial/right ventricular interferences are compared, the atrial lead is more susceptible to electromagnetic fields. CLINICAL TRIAL REGISTRATION URL: http://clinicaltrials.gov/ct2/show/NCT01626261. Unique identifier: NCT01626261.
Napp et al. (Sat,) conducted a observational in Patients with implantable cardioverter-defibrillators (n=110). Electric and magnetic 50-Hz fields was evaluated on Interference thresholds and sensing disturbances. Exposure to strong 50-Hz electromagnetic fields caused right ventricular sensing disturbances in 5% and right atrial disturbances in 45% of ICD patients at nominal sensitivity.