Safe New Technologies, Finnish Institute of Occupational Health, Helsinki, Finland.
Scand Cardiovasc J. 2012 Oct;46(5):308-14. doi: 10.3109/14017431.2012.716525. Epub 2012 Aug 21.
The aim of this study was to find the electromagnetic interference (EMI) thresholds for several commonly used implantable cardioverter-defibrillators (ICD).
Seventeen ICDs were exposed to magnetic fields with different intensities produced by the Helmholtz coil system. Sinusoidal, pulse, ramp, and square-waveforms with a frequency range of 2 Hz to 1 kHz were used.
ICD malfunctions occurred in 11 of the 17 ICDs tested. The ICD malfunctions that occurred were false detections of ventricular tachycardia (6/17 ICDs) and ventricular fibrillation (3/17 ICDs), false detection of atrial tachycardia (4/6 dual chamber ICDs) and tachycardia sensing occurring during atrial or ventricular refractory periods (1/17 ICD). In most cases, no interference occurred at magnetic field levels below the occupational safety limits of the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Nevertheless, some frequencies using sine, ramp or square waveforms did interfere with certain ICDs at levels below these limits. No EMI occurred with any of the ICDs below the ICNIRP limits for public exposure.
Evaluation of EMI should be part of the risk assessment of an employee returning to work after an ICD implantation. The risk assessment should consider magnetic field intensities, frequencies and waveforms.
本研究旨在确定几种常用植入式心脏复律除颤器（ICD）的电磁干扰（EMI）阈值。
将 17 个 ICD 暴露于亥姆霍兹线圈系统产生的不同强度磁场中。使用频率范围为 2 Hz 至 1 kHz 的正弦波、脉冲波、斜坡波和方波。
在测试的 17 个 ICD 中有 11 个发生了 ICD 故障。发生的 ICD 故障包括假阳性室性心动过速（6/17 个 ICD）和心室颤动（3/17 个 ICD）、假阳性房性心动过速（4/6 个双腔 ICD）和心动过速感知在心房或心室不应期期间发生（1/17 个 ICD）。在磁场水平低于国际非电离辐射防护委员会（ICNIRP）职业安全限值的情况下，大多数情况下不会发生干扰。然而，某些使用正弦波、斜坡波或方波的频率在低于这些限值的水平下会干扰某些 ICD。在任何 ICD 低于 ICNIRP 公众暴露限值的情况下，均未发生 EMI。
在 ICD 植入后员工返回工作时，应将 EMI 评估作为员工风险评估的一部分。风险评估应考虑磁场强度、频率和波形。
