Hazards of an Alternative Medicine Device in a Patient with a Pacemaker
http://www.100md.com
《新英格兰医药杂志》
To the Editor: Both patients and health care professionals should be aware of potential pacemaker interactions in the environment, since cardiac pacemakers and defibrillators are sensitive to many kinds of electromagnetic interference.
A 52-year-old man with a dual-chamber pacemaker, implanted because of intermittent, symptomatic, high-degree atrioventricular block, presented with short episodes of dizziness and near-fainting. A detailed history revealed that the symptoms occurred exclusively during self-prescribed therapy with a Zapper device. The Zapper, which is available worldwide, is a simple, battery-powered, direct-current–offset pulse generator with square-wave output at a constant frequency of 33.3 kHz ±10 percent. These electronic pulse frequencies are applied to both hands. The Zapper is an alternative medicine treatment, which is used regularly "to eliminate cancer, other chronic illnesses, self-diagnosed parasites and germs."1
A thorough assessment of the pacemaker in our patient showed that all settings and function were within normal limits. During atrial synchronous ventricular pacing (Figure 1A), high-frequency signals at a rate of 143 beats per minute were visible during use of the Zapper. Ventricular oversensing with inhibition of the pacemaker occurred with increasing direct-current amplitude (Figure 1B). During use of the Zapper, the symptoms could be reproduced, and the electrocardiogram showed a slow ventricular escape rhythm (Figure 1C).
Figure 1. Electrocardiograms Obtained before and during Use of the Zapper Device.
Panel A shows normal atrial synchronous ventricular pacing and the high-frequency signals at a rate of 143 beats per minute (arrow) during use of the Zapper device. Panel B shows ventricular oversensing with inhibition of the pacemaker with increasing direct-current amplitude. During ongoing use of the Zapper device, the symptoms could be reproduced, and the electrocardiogram in Panel C shows a slow ventricular escape rhythm. AV denotes atrioventricular.
Pacemakers and defibrillators are frequently exposed to a "hostile" electromagnetic environment from a variety of external sources. These include magnetic resonance imaging (MRI) equipment, metal detectors, antitheft devices, household appliances, some digital cellular phones, and power tools.2 The most frequent adverse responses to electromagnetic interference are inappropriate temporary inhibition, as documented in our patient, or triggering of pacemaker stimuli and reversion to asynchronous pacing. Inappropriate reprogramming and permanent damage to the device circuitry or the electrode-to-tissue interface are less frequent complications. As a result of the development of bipolar sensing circuits and sophisticated filtering techniques, the risk of pacemaker dysfunction has been reduced markedly. The hospital remains a potentially dangerous environment, with an array of diagnostic sources of electromagnetic interference (e.g., MRI) as well as therapeutic sources (direct-current cardioversion, electrocautery, and neurostimulation).3,4 Despite being cautioned about exposure to environmental magnetic fields and in disregard of the warning on the device package, our patient used the Zapper and had symptomatic bradycardia because of ventricular oversensing. This case demonstrates the need to consider unusual sources of electromagnetic interference in symptomatic patients with implanted pacemakers or defibrillators.
Marcel Furrer, M.D.
Barbara Naegeli, M.D.
Osmund Bertel, M.D.
Stadtspital Triemli
8063 Zurich, Switzerland
barbara.naegeli@triemli.stzh.ch
References
Clark HR. The cure for all diseases. Chula Vista, Calif.: New Century Press, 1995.
Pinski SL, Trohman RG. Interference in implanted cardiac devices. Pacing Clin Electrophysiol 2002;25:1367-81, 1496.
Eriksson M, Schüller H, Sj?lund B. Hazard from transcutaneous nerve stimulation in patients with pacemakers. Lancet 1978;1:1319-1319.
Pyatt JR, Trenbath D, Chester M, Connelly DT. The simultaneous use of a biventricular implantable cardioverter defibrillator (ICD) and transcutaneous electrical nerve stimulation (TENS) unit: implications for device interaction. Europace 2003;5:91-93.
A 52-year-old man with a dual-chamber pacemaker, implanted because of intermittent, symptomatic, high-degree atrioventricular block, presented with short episodes of dizziness and near-fainting. A detailed history revealed that the symptoms occurred exclusively during self-prescribed therapy with a Zapper device. The Zapper, which is available worldwide, is a simple, battery-powered, direct-current–offset pulse generator with square-wave output at a constant frequency of 33.3 kHz ±10 percent. These electronic pulse frequencies are applied to both hands. The Zapper is an alternative medicine treatment, which is used regularly "to eliminate cancer, other chronic illnesses, self-diagnosed parasites and germs."1
A thorough assessment of the pacemaker in our patient showed that all settings and function were within normal limits. During atrial synchronous ventricular pacing (Figure 1A), high-frequency signals at a rate of 143 beats per minute were visible during use of the Zapper. Ventricular oversensing with inhibition of the pacemaker occurred with increasing direct-current amplitude (Figure 1B). During use of the Zapper, the symptoms could be reproduced, and the electrocardiogram showed a slow ventricular escape rhythm (Figure 1C).
Figure 1. Electrocardiograms Obtained before and during Use of the Zapper Device.
Panel A shows normal atrial synchronous ventricular pacing and the high-frequency signals at a rate of 143 beats per minute (arrow) during use of the Zapper device. Panel B shows ventricular oversensing with inhibition of the pacemaker with increasing direct-current amplitude. During ongoing use of the Zapper device, the symptoms could be reproduced, and the electrocardiogram in Panel C shows a slow ventricular escape rhythm. AV denotes atrioventricular.
Pacemakers and defibrillators are frequently exposed to a "hostile" electromagnetic environment from a variety of external sources. These include magnetic resonance imaging (MRI) equipment, metal detectors, antitheft devices, household appliances, some digital cellular phones, and power tools.2 The most frequent adverse responses to electromagnetic interference are inappropriate temporary inhibition, as documented in our patient, or triggering of pacemaker stimuli and reversion to asynchronous pacing. Inappropriate reprogramming and permanent damage to the device circuitry or the electrode-to-tissue interface are less frequent complications. As a result of the development of bipolar sensing circuits and sophisticated filtering techniques, the risk of pacemaker dysfunction has been reduced markedly. The hospital remains a potentially dangerous environment, with an array of diagnostic sources of electromagnetic interference (e.g., MRI) as well as therapeutic sources (direct-current cardioversion, electrocautery, and neurostimulation).3,4 Despite being cautioned about exposure to environmental magnetic fields and in disregard of the warning on the device package, our patient used the Zapper and had symptomatic bradycardia because of ventricular oversensing. This case demonstrates the need to consider unusual sources of electromagnetic interference in symptomatic patients with implanted pacemakers or defibrillators.
Marcel Furrer, M.D.
Barbara Naegeli, M.D.
Osmund Bertel, M.D.
Stadtspital Triemli
8063 Zurich, Switzerland
barbara.naegeli@triemli.stzh.ch
References
Clark HR. The cure for all diseases. Chula Vista, Calif.: New Century Press, 1995.
Pinski SL, Trohman RG. Interference in implanted cardiac devices. Pacing Clin Electrophysiol 2002;25:1367-81, 1496.
Eriksson M, Schüller H, Sj?lund B. Hazard from transcutaneous nerve stimulation in patients with pacemakers. Lancet 1978;1:1319-1319.
Pyatt JR, Trenbath D, Chester M, Connelly DT. The simultaneous use of a biventricular implantable cardioverter defibrillator (ICD) and transcutaneous electrical nerve stimulation (TENS) unit: implications for device interaction. Europace 2003;5:91-93.