Gwechenberger Marianne, Rauscha Friedrich, Stix Günter, Schmid Gernot, Strametz-Juranek Jeanette
Department of Cardiology, Medical University of Vienna, Austria.
Bioelectromagnetics. 2006 Jul;27(5):365-77. doi: 10.1002/bem.20217.
A commercially available magnetic therapy system, designed for clinical application as well as for private use without medical supervision, was examined with respect to its potential for causing electromagnetic interference with implantable pacemakers (PMs) and automatic implantable cardioverter defibrillators (AICDs). A sample of 15 PMs and 5 AICDs were experimentally investigated. Each of the implants was realistically positioned in a homogeneous, electrically passive torso phantom and exposed to the magnetic fields of the system's applicators (whole body mat, cushion, and bar applicator). The detection thresholds of the implants were programmed to maximum sensitivity and both unipolar as well as bipolar electrode configurations were considered. The evaluation of possible interferences was derived from the internal event storages and pacing statistics recorded by the implants during exposure. Any "heart activity" recorded by the implants during exposure was interpreted as a potential interference, because the implant obviously misinterpreted the external interference signal as a physiological signal. Only cases without any recorded "heart activity" and with nominal pacing rates (as expected from the program parameter settings) of the implants were rated as "interference-free." Exposure to the whole body mat (peak magnetic induction up to 265 microT) did not show an influence on PMs and AICD in any case. The cushion applicator at the highest field intensity (peak magnetic induction up to 360 microT) led to atrial sensing defects in four PM models with unipolar electrode configuration. Under bipolar electrode configuration no disturbances occurred. The bar applicator led to sensing problems and consecutively reduced pacing rates in all tested PM models under unipolar electrode configuration and maximum field intensity (peak magnetic induction up to 980 microT). Bipolar electrode configuration resolved the problem. The investigated AICDs did not show malfunctions under any investigated condition. In conclusion, the examined PEMF therapy system did not interfere with the investigated implantable cardiac devices with bipolar electrode configuration. However, unipolar electrode configuration in pacemakers seems to be potentially hazardous during application of the examined PEMF therapy system.
对一种市售的磁疗系统进行了检测，该系统设计用于临床应用以及在无医疗监督的情况下供个人使用，检测其对植入式起搏器（PM）和自动植入式心脏复律除颤器（AICD）产生电磁干扰的可能性。对15个PM和5个AICD样本进行了实验研究。每个植入装置都被实际放置在一个均匀的、电无源的人体躯干模型中，并暴露于该系统的施疗器（全身垫、靠垫和棒状施疗器）的磁场中。将植入装置的检测阈值设定为最大灵敏度，并考虑了单极和双极电极配置。通过植入装置在暴露期间记录的内部事件存储和起搏统计数据来评估可能的干扰。植入装置在暴露期间记录的任何“心脏活动”都被解释为潜在干扰，因为植入装置显然将外部干扰信号误判为生理信号。只有在没有记录到任何“心脏活动”且植入装置的起搏率为标称值（根据程序参数设置预期）的情况下，才被评为“无干扰”。暴露于全身垫（峰值磁感应强度高达265微特斯拉）在任何情况下都未对PM和AICD产生影响。在最高场强（峰值磁感应强度高达360微特斯拉）下，靠垫施疗器导致4个采用单极电极配置的PM模型出现心房感知缺陷。在双极电极配置下未发生干扰。在单极电极配置和最大场强（峰值磁感应强度高达980微特斯拉）下，棒状施疗器在所有测试的PM模型中均导致感知问题并相继降低起搏率。双极电极配置解决了该问题。在所研究的任何条件下，所研究的AICD均未出现故障。总之，所检测的脉冲电磁场治疗系统在采用双极电极配置时不会干扰所研究的植入式心脏装置。然而，在应用所检测的脉冲电磁场治疗系统时，起搏器中的单极电极配置似乎存在潜在危险。
