The Combined Transvenous Implantation of Cardioverter Defibrillators and Permanent Pacemakers

We developed criteria for implantation and programming of permanent endocardial pacemakers in patients with a nonthoracotomy ICD system. These criteria were prospectively used in 10 patients who recieved an ICD prior to (n = 5) or following (n = 5) implantation of a dual chamber (n = 6) or ventricular (n = 4) pacemaker with a unipolar (n = 4) or bipolar (n = 6) lead configuration. All patients were tested for interactions or malfunctions. Undersensing of ventricular fibrillation by the atrial sense amplifier and inadequate atrial pacing occurred in one patient with a unipolar dual chamber system programmed to AAIR but didn't impair ICD sensing. Transient or permanent loss of capture or sensing of the pacemaker was not observed after ICD shocks with the output programmed to double pulse width and voltage of stimulation threshold and the sensitivity to 50% of the detected R wave. One episode of transient reprogramming occurred without clinical consequences. One unipolar ventricular pacemaker lead had to be exchanged against a bipolar lead because of oversensing of the pacing artifact by the ICD. There was no failure of an ICD to detect ventricular arrhythmias due to inadequate pacemaker activity. During a follow-up period of 21 ± 11 months, a total of 78 ventricular arrhythmias were effectively treated in six patients. Thus, a combined use of transvenous ICD and pacemaker is possible despite the close vicinity of pacing and defibrillations leads. Optimized programming different to the common settings is required. As interactions occurred only in unipolar pacemaker leads bipolar systems should be used in these patients.     

A prospective randomized-controlled trial of ventricular fibrillation detection time in a DDDR ventricular defibrillator. Ventak AV II DR Study Investigators

Implantable cardioverter defibrillators (ICDs) with dual chamber and dual chamber rate responsive pacing may offer hemodynamic advantages for some ICD patients. Separate ICDs and DDDR pacemakers can result in device to device interactions, inappropriate shocks, and underdetection of ventricular fibrillation (VF). The objectives of this study were to compare the VF detection times between the Ventak AV II DR and the Ventak AV during high rate DDDR and DDD pacing and to test the safety of dynamic ventricular refractory period shortening. Patients receiving an ICD were randomized in a paired comparison to pacing at 150 beats/min (DDD pacing) or 175 beats/min (DDDR pacing) during ICD threshold testing to create a "worst case scenario" for VF detection. The VF detection rate was set to 180 beats/min, and VF was induced during high rate pacing with alternating current. The device was then allowed to detect and treat VF. The induction was repeated for each patient at each programmed setting so that all patients were tested at both programmed settings. Paired analysis was performed. Patient characteristics were a mean age of 69 +/- 11 years, 78% were men, coronary artery disease was present in 85%, and a mean left ventricular ejection fraction of 0.34 +/- 0.11. Fifty-two episodes of VF were induced in 26 patients. Despite the high pacing rate, all VF episodes were appropriately detected. The mean VF detection time was 2.4 +/- 1.0 seconds during DDD pacing and 2.9 +/- 1.9 seconds during DDDR pacing (P = NS). DDD and DDDR programming resulted in appropriate detection of all episodes of VF with similar detection times despite the "worst case scenario" tested. Delays in detection may be seen with long programmed ventricular refractory periods which shorten the VF sensing window and may be avoided with dynamic ventricular refractory period shortening.     

Use of a transurethral microwave thermotherapeutic device with permanent pacemakers and implantable defibrillators

OBJECTIVE: To determine whether a device (Urologix Targis system) used for transurethral microwave treatment interferes with sensing, pacing, and arrhythmia detection by permanent pacemakers and implantable cardioverter-defibrillators (ICDs). METHODS: We tested 13 pacemakers in both bipolar and unipolar sensing configurations and 8 ICDs in vitro. Pacemakers and ICDs were programmed to their most sensitive settings. Energy outputs of the microwave device were typical of those used clinically. The probe of the microwave device was anchored 1.2 cm from the pacemaker or ICD being tested. RESULTS: No sensing, pacing, or arrhythmic interactions were noted with any ICD or any pacemaker programmed to the bipolar configuration. One pacemaker (Guidant Vigor 1230) showed intermittent tracking when programmed to the unipolar configuration. CONCLUSIONS: Most patients with permanent pacemakers or ICDs can safely undergo transurethral microwave therapy using the device tested. Pacemakers and ICDs should be programmed to the bipolar configuration (if available) during therapy. The pacemaker or ICD should be interrogated before and after therapy to determine whether programming changes occurred as a result of treatment. However, our findings suggest that this is unlikely.     

Upgrade of permanent pacemakers and single chamber implantable cardioverter defibrillators to pectoral dual chamber implantable cardioverter defibrillators: indications,surgical approach,and long-term clinical results

The aim of this study was to describe the indications for upgrade of pacemakers (PMs) or single chamber (VVIR) ICDs to dual chamber (DDDR) ICDs, surgical approach, hardware hybridization, and clinical outcome. Patients with preexisting PMs or VVIR ICDs may develop indications for ICD therapy or dual chamber pacing, respectively, that can be served by DDDR ICDs that incorporate preexisting transvenous leads. Fifty-seven patients underwent upgrade from PMs (29/57) or VVIR ICDs (28/57) to pectoral DDDR ICDs. Preexisting transvenous atrial and/or ventricular leads suitable for continued use were incorporated into new DDDR ICDs in 88.5% and 100% of PM and VVIR ICD upgrades, respectively. Acceptable DFTs were achieved in 56 (98.2%) of 57 patients. Appropriate VT/VF therapies were registered among 33.3% of patients during follow-up. No shocks due to lead noise were observed in any patient with hybridized transvenous leads. Atrial far-field R wave (FFRW) oversensing occurred in 24% of DDDR ICD systems incorporating a preexisting atrial lead. FFRW was overcome by programming reduced atrial sensitivity without interfering with the normal ICD system performance in all instances. Upgrade of PMs and VVIR ICDs to pectoral DDDR ICDs is safe and technically feasible in most patients. Preexisting transvenous leads can be successfully incorporated into new DDDR ICDs, simplifying the surgical procedure, minimizing transvenous hardware, and eliminating the possibility of hazardous pacemaker-ICD interactions.     

Safety of Pacemaker Implantation in Patients with Transvenous (Nonthoracotomy) Implantable Cardioverter Defibrillators

While several reports bave documented the safety of implantation of transvenous pacemakers in patients with epicardial patch-based impiantable cardioverter defibrillators (ICDs), the implantation of transvenous pacemakers in patients with transvenous (nonthoracotomy) ICDs has not been well-descrihed. We present three patients with transvenous ICDs who subsequently underwent implantation of transvenous pacemakers without complication. Technical considerations and a testing protocol for detection of pacemaker-ICD interactions are discussed.     

Decrease in Canine Endocardial and Epicardial Electrogram Voltages with Exercise: Implications for Pacemaker Sensing

Individuals with permanently implanted pacemakers who have normal sensing and pacing at rest may demonstrate abnormalities, particularly of atrial sensing, with exercise. Exercise is known to cause changes in the surface electrocardiographic voltages. The purpose of this study was to evaluate changes in endocardial and epicardial voltages during exercise in canines with permanently implanted pacing leads similar to those permanently implanted in humans with pacemakers. Six adult mongrel dogs were equipped with transvenous atrial and ventricular endocardial bipolar screw-in leads from a jugular venosection, and with atrial and ventricular bipolar stab-on leads from a left thoracotomy. Exercise was performed at one week following implantation and at weekly intervals for a total of 4 weeks. The animals were studied at rest and at a single workload of 3 miles per hour at a 30% elevation. Unfiltered electrograms were recorded with a VR-12 Electronics-for-Medicine photographic recorder. The mean decreases of electrograms with exercise from resting voltage were: 15% for atrial endocardial unipolar leads; 11% for atrial endocardial bipolar leads; 4% for atrial epicardial unipolar leads; 15% for atrial epicardial bipolar leads; 8% for ventricular endocardial unipolar leads; 18% for ventricular endocardial bipolar leads; 0.1% for ventricular epicardial unipolar leads and 5% for ventricular epicardial bipolar leads.     

Intracardiac Emergency Defibrillation for Refractory Ventricular Fibrillation During Implantation of Cardioverter Defibrillators with Nonthoracotomy Lead Systems

Implantable cardioverter defibrillators (ICDs) are being implanted in increasing numbers. At inlraoperative defibrillation threshold tests refractory ventricular fibrillation (VF) requiring emergency open chest resuscitation is a major concern during impiantation of nonthoracotomy ICD lead systems. A new method of high energy endocardial/extrathoracic defibrillotion via the implanted ICD transvenous defibrillation electrode (TDE) was used to terminate refractory VF. During implantation of ICD with TDE in 20 patients refractory VF occurred in two patients. The arrhythmia was terminated with endocardial/extrathoracic defibrillation in both cases, and no complications were observed.     

The 11th world survey of cardiac pacing and implantable cardioverter-defibrillators: calendar year 2009--a World Society of Arrhythmia's project

A worldwide cardiac pacing and implantable cardioverter-defibrillator (ICD) survey was undertaken for calendar year 2009 and compared to a similar survey conducted in 2005. There were contributions from 61 countries: 25 from Europe, 20 from the Asia Pacific region, seven from the Middle East and Africa, and nine from the Americas. The 2009 survey involved 1,002,664 pacemakers, with 737,840 new implants and 264,824 replacements. The United States of America (USA) had the largest number of cardiac pacemaker implants (225,567) and Germany the highest new implants per million population (927). Virtually all countries showed increases in implant numbers over the 4 years between surveys. High-degree atrioventricular block and sick sinus syndrome remain the major indications for implantation of a cardiac pacemaker. There remains a high percentage of VVI(R) pacing in the developing countries, although compared to the 2005 survey, virtually all countries had increased the percentage of DDDR implants. Pacing leads were predominantly transvenous, bipolar, and active fixation. The survey also involved 328,027 ICDs, with 222,407 new implants and 105,620 replacements. Virtually all countries surveyed showed a significant rise in the use of ICDs with the largest implanter being the USA (133,262) with 434 new implants per million population. This was the largest pacing and ICD survey ever performed, because of mainly a group of loyal enthusiastic survey coordinators. It encompasses more than 80% of all the pacemakers and ICDs implanted worldwide during 2009.     

Comparison of Myopotential Interference in Unipolar-Bipolar Programmable DDD Pacemakers

Myopotential interference (MPI) can inhibit or trigger single and dual chamber unipolar pacemakers while bipolar pacemakers are resistant. Twenty units of two different models of dual chamber pacemaker, each capable of being programmed to single chamber or dual chamber and unipolar or bipolar function were tested to provoke myopotential interference. No patient had evidence of myopotential interference at any sensitivity setting in the bipolar configuration either in atrium or in ventricle. All patients (20/20) interfered with pacemaker function at the highest atrial or ventricular sensitivity settings in the unipolar configuration. T wave sensing occurred at the 0.25 mV sensitivity setting in four patients in pacemaker model 925, in both bipolar and unipolar configurations. Twenty-five percent of patients had myopotential interference at the unipolar atrial sensing threshold and did not allow a setting which would reject myopotential interference while providing satisfactory atrial sensing. Twenty percent (2/10) had myopotential caused ventricular inhibition at the least sensitive ventricular channel setting in model 240G so that myopotential interference could not be avoided in that unit no matter how large the electrogram.     

Inappropriate Sensing of Atrial Stimuli in Patients with Third-Generation Defibrillators and DDD Pacemakers

Although the problem of ICD sensing of paced ventricular stimuli has been resolved by incorporation of VVI pacing into current ICDs, many patients require separate DDD pacemakers. We report a problematic PM-ICD interaction: the inability to prevent sensing of paced atrial stimuli (atrial sensing) leading to double-counting in DDD-PM-requiring patients with transvenous (TV) ICDs with aggressive autogain sensing (CPI Ventak® PRxII or III). Four of eight patients receiving both transvenous DDD PMs and ICDs (CPI Endotak® lead, at the RV apex), had atrial sensing, leading to double counting, despite intraoperative testing of multiple atrial locations with an active fixation lead. Five patients had a PRxlI/III ICD, four with atrial sensing (80%), and three a PRx without atrial sensing. Patients with atrial sensing were not distinguished by any clinical or device related variable. In patients with atrial sensing (all with heart block), the PM was programmed to VDD mode. No patient has received inappropriate therapy or failed to sense VP in follow-up. In many patients with TV ICDs who require DDD pacing, no atrial position can be found without ICD sensing of atrial stimuli. While in patients with heart block this problem can be circumvented by programming to the VDD mode, in patients with sinus incompetence it may only be resolved by the combination ICD-DDD PM, currently in development.     

Transcutaneous T Wave Shock: A Universal Method for Ventricular Fibrillation Induction

Our objective was to develop a universal noninvasive method for VF induction. ICD implantation requires VF induction. Conventional rapid ventricular stimulation may fail to induce VF. Some ICDs can deliver low energy shocks on the T wave to induce VF. We hypothesized that an external dual chamber pacemaker and an external defibrillator could be configured to allow reliable VF induction with any ICD system. A surface ECC signal was delivered to the atrial channel of an external dual chamber DDD pacemaker. The 'AV' delay was adjusted so that the ventricular output of the pacemaker was delivered to an external defibrillator synchronized to deliver 5–50 J. Twenty-six patients at ICD implant or follow-up had VF induced in native rhythm (sinus rhythm or atrial fibrillation), or during a ventricular pacing train (3–8 beats at cycle length 500–880 ms). VF was successfully induced in 14 of 25 (56%) patients in native rhythm; and in 16 of 17 (94%) patients during pacing (P = 0.013). VF induction success rate was 36% in native rhythm (31/86 attempts) and 88% during pacing (69/78 attempts) (P < 0.001). The 'R' to shock interval was 269 ± 31 ms in native rhythm and 257 ± 48 ms during pacing. Energy delivered from the external defibrillator was 19 ± 3 J in native rhythm and 21 ± 6 J during pacing. We concluded that VF induction by synchronizing a small external shock to the T wave is a fast, effective way to reliably ensure arrhythmia induction with any ICD at implant or follow-up. This method is more successful during pacing than in sinus rhythm.     

Unexpected loss of bipolar pacing with implanted dual chamber pacemakers

Bipolar leads are most commonly used in the current practice of pacemaker therapy. In our study of 124 patients implanted with Guidant/Cardiac Pacemakers (CPI) Vigor dual chamber pacemakers, 5 patients had unexpectedly abrupt increases in bipolar lead impedance and pacing threshold 2 weeks to 18 months postimplantation without changes in sensing function. With the lead configuration reprogrammed to unipolar, the lead impedance and pacing threshold were restored to appropriate ranges. The changes in bipolar lead parameters can be caused by the CPI's "Quick Connect" (QC1) header lead system incorporated in these pacemakers.     

Survey of cardiac pacing and implanted defibrillator practice patterns in the United States in 1997

A survey of implanters of permanent cardiac pacemakers and ICDs in the United States during 1997 was conducted to identify present and changing patterns in indications for pacing, implantation techniques, pacing-mode selection, follow-up, and opinions regarding pacing and ICD related issues. This report is an update from 1993 of surveys performed every 4 years for the International Cardiac Pacing and Electrophysiology Society (ICPES). Questionnaires were sent to implanting physicians who were members of the North American Society of Pacing and Electrophysiology (NASPE), and who might, therefore, be expected to be more conversant than others with the state of the art. Four major manufacturers also provided estimates of the numbers of pacemakers and ICDs implanted in the United States from 1994 through 1997. In 1997, approximately 182,000 new rhythm management devices, including 153,000 primary pacing systems and 29,000 ICDs, were implanted, an increase of 24% for pacemakers and 90% for ICDs since 1994. In 1997, pacemaker implantations were performed by about 8,600 physicians working in 3,300 hospitals and 1,000 independent "surgi-centers." From 1994 to 1997, sales in the United States of dual chamber pacemakers rose from 58% to 69% of the total, and adaptive rate systems from 74% to 90%. ICD sales increased by about 29% per year from 18,700 to 35,000 units. This study disclosed significant differences among implanter subcategories and between present and earlier practices, and it provided useful insights into trends in pacemaker and defibrillator practice. Future surveys would be facilitated if a standardized implant registry like that used in Europe were established in the United States.     

Multicenter Experiences with a Single Lead Electrode for Dual Chamber ICD Systems

Monitoring of atrial signals improves the accuracy in identifying supraventricular tachyarrhythmias to prevent inappropriate therapies in patients with implantable ICDs. Since difficulties due to the additional atrial lead were found in dual chamber ICD systems with two leads, the authors designed a single pass VDD lead for use with dual chamber ICDs. After a successful animal study, the prototype VDD lead (single coil defibrillation lead with two additional fractally coated rings for bipolar sensing in the atrium) was temporarily used in 30 patients during a German multicenter study. Atrial and ventricular signals were recorded during sinus rhythm (SR), atrial flutter, AF, and VT or VF. The implantation of the lead was successful in 27 of 30 patients. Mean atrial pacing threshold was 2.5 +/- 0.9 V/0.5 ms, mean atrial impedance was 213 +/- 31 ohms. Atrial amplitudes were greater during SR (2.7 +/- 1.6 mV) than during atrial flutter (1.46 +/- 0.3 mV, P < 0.05) or AF (0.93 +/- 0.37 mV, P < 0.01). During VF atrial "sinus" signals had significantly (P < 0.01) lower amplitudes (1.4 +/- 0.52 mV) than during SR. The mean ventricular sensing was 13.3 +/- 7.9 mV and mean ventricular impedance was 577 +/- 64 ohms. Defibrillation was successful with a 20-J shock in all patients. In addition, 99.6% of P waves could be detected in SR and 84.4% of flutter waves during atrial flutter. During AF, 56.6% of atrial signals could be detected without modification of the signal amplifier. In conclusion, a new designed VDD dual chamber lead provides stable detection of atrial and ventricular signals during SR and atrial flutter. Reliable detection of atrial signals is possible without modification of the ICD amplifier.     

Interactions between Pacemakers and Security Systems

Electromagnetic fields arising from a variety of different sources have been shown to interfere with normal pacemaker function. This study evaluated the possible interactions between two modern security systems and different pacemaker types. Fifty–three patients (27 single chamber pacemakers, 25 dual chamber pacemakers) have been tested routinely for their pacemaker function. Thirty–eight patients presented with unipolar sensing and 15 with bipolar sensing. The patients were asked to walk through an installed security system, an antitheft device, and electromagnetic access device with different field strengths while a six–channel ECG monitored the patients. The pacemaker systems were first measured in their basic programmed modes, then the intervention frequency was changed to 100/min and, thereafter, the maximum sensitivity without T wave over– sensing was added. In the security system with the highest field strength (2,700 mA/m), a pacemaker malfunction could be observed in 13% of the monitored patients. In one case, a pacemaker (VVIR) switched to ventricular safety pacing (VOO mode). In the security system with the lower field strength (1,600 mA/m) we found a pacemaker malfunction in 4% of the tested patients. In the antitheft device (50 mA/m). in the electromagnetic access device (300 mA/m), and in pacemaker systems with bipolar sensing, none of these dysfunctions were observed. Phantom programming as described previously did not occur in any of the systems. Persons who are often in the vicinity of security systems should be equipped with a bipolar pacemaker system. Our findings indicate that patients with pacemakers should avoid contact with security systems.     

Interactions Between Transvenous Nonthoracotomy Cardioverter Defibrillator Systems and Permanent Transvenous Endocardial Pacemakers

Limited information is available regardIng potential adverse Interactions between transvenous nonthoracotomy cardioverter defibrillators and pacemakers. We describe our experience with 37 patients who have undergone successful Implantation of both a transvenous defibrillator and pacemaker. The patients’mean age was 64 ± 12,9 years. Thirty-three were male and four were female. The mean LVEF wos 30.8%±11.8%, The indications for pacemaker implantation included sick sinus syndrome in 13 patients, complete heart block in 15 patients, sinus brady-cardia secondary to medications In 8 patients, and neurocardlogenlc syncope In 1 patient. The Indications for Insertion of a defibrillator Included medically refractory VT in 27 patients and sudden cardiac death in 10 patients. Twenty-three patients received an Endotak lead and 14 patients received o Transvene lead. Eighteen patients had a pacemaker prior to an ICD, 14 patients had an ICD prior to a pacemaker, and 4 patients had both devices placed simultaneously. Interaction was evaluated at Implant of the second device and 1–3 days after both devices were placed. Detection of VF/VT was analyzed during asynchronous pacing (DOO/VOO) with maximum pacing output. In addition, in six patients, DFT was determined before and after pacemaker implantation. In 14 patients (38%), device interactions that could not always be optimally corrected were observed. In five patients, the pacemaker was reset to the “noise reversion” mode after high energy ICD discharge, Oversensing of atrial pacemaker stimuli resulted in inappropriate ICD firings in four patients. This wos observed only with a specific device ond could not be prevented by atriol leod repositioning in two of them, but required reprogramming of the pacemaker to the VVImode. An increase in DFT was observed in five patients who had a pacemaker implanted after on ICD. Compared with previously published studies, a greater frequency of tronsvenous ICD and pacemaker Interactions were observed. Considering that almost 50% of the patients already have o pacemaker ot the time of ICD Implant, the ovalloblllty of deflbrlllotors with dual chamber pocing capability will not eliminate the potential for this problem.     

Preliminary Clinical Experience with the First Dual Chamber Pacemaker Defibrillator

The lack of specificity of VT detection is a significant shortcoming of current ICDs. In a French multicenter study, 18 patients underwent implantation of the Defender 9001 (ELA Medical), an ICD utilizing dual chamber pacing and arrhythmia detection. Over a mean follow-up period of 7.1 ± 4.5 months, 176 tachycardia episodes recorded in the device memory were analyzed, and physician diagnosis was compared with that by the device. All 122 VT/VF episodes were correctly diagnosed, as were 51 of 53 supraventricular tachyarrhythmias. Two episodes of AF with rapid regular ventricular rates were treated as VT, and a third episode, treated as VT, could not be diagnosed with certainty. A dual chamber pacemaker defibrillator offers improved diagnostic specificity without loss of sensitivity, in addition to the hemodynamic benefit of dual chamber pacing. (PACE 1997;20     

Ventricular Fibrillation Induction Using Nonsynchronized Low Energy External Shock During Rapid Ventricular Pacing: Method of Induction When Fibrillation Mode of ICD Fails

Third-generation implantable cardioverter defibrillators (ICD) are frequently implanted with non-thoracotomy systems and provide noninvasive methods for electrical stimulation and ventricular fibrillation induction. These modalities facilitate postoperative testing of the ICD. Rapid right ventricular burst pacing via the defibrillator is commonly used for initiation of ventricular tachyarrhythmias. However, with the available third-generation devices, ventricular fibrillation (VF) induction may be impossible in up to 19% of the patients. In these cases, transvenous placement of a right ventricular catheter has been required to generate VF and appropriately evaluate the device. We report a new technique of noninvasive induction of VF using a low energy external nonsynchronized shock delivered during ICD fibrillation induction pacing. In three patients, after all efforts to induce VF by the Ventritex Cadence V-100 had failed, a 20 J nonsynchronized shock was delivered during rapid RV pacing. This resulted in VF on the first attempt in all patients. This noninvasive technique of VF initiation may provide a useful clinical approach to ICD testing that eliminates the costs and risks of an invasive procedure.     

Importance of Pacemaker Noise Reversion as a Potential Mechanism of Pacemaker-ICD Interactions

Numerous types of interactions between pacemakers and implantable cardioverter defibrillators (ICDs) have been described. Pacemaker outputs preventing appropriate detection of ventricular tachycardia or ventricular fibrillation by the ICD is one of the more serious. Asynchronous pacemaker activity during ventricular arrhythmias maybe caused by either nonsensing of the arrhythmia or by noise reversion, which is an algorithm that causes the pacemaker to switch to asynchronous pacing when repetitive sensing at a high rate occurs. We analyzed the mechanisms underlying asynchronous pacemaker activity in ventricular arrhythmias using pacemaker telemetry during the arrhythmia. Thirty-nine induced arrhythmias from 26 different procedures in 19 patients with both pacemakers and ICDs were analyzed. Of the 39 arrhythmias, asynchronous pacemaker activity occurred in 16. The underlying mechanism was nonsensing in 4 episodes and noise reversion in 12 episodes. Clinically significant interference with detection arose on three occasions. Conditions favoring the occurrence of noise reversion include specific pacemaker models, arrhythmia cycle lengths in the range causing noise reversion of the individual pacemaker model, long noise sampling periods, and VVI pacing mode. Noise reversion can be diagnosed by telemetering the pacemaker marker channel during ventricular arrhvthmias as a part of routine pacemaker-ICD interaction evaluation. It can be prevented or minimized by programming short ventricular refractory periods or using pacemakers with shoii retriggerable refractory periods.     

Study of Pacemaker and Implantable Cardioverter Defibrillator Triggering by Electronic Article Surveillance Devices (SPICED TEAS)

The magnetic fields emitted by electronic article surveillance (EAS) systems (shoplifting gates) are a source of interference for implanted medical devices. In the Study of Pacemaker and Implantable Cardioverter Defibrillator Triggering by Electronic Article Surveillance Devices (SPICED TEAS), 25 adult volunteers with ICDs and 50 with pacemakers were exposed to the fields of six different EAS systems. These EAS systems used three modes of operation: magnetic audio frequency, swept radio frequency, and acoustomagnetic technology. No ICD exhibited interference mimicking sensing of tachyarrhythmias with any EAS system. Pacemakers interacted variably, depending on the type of EAS system. Swept radiofrequency systems produced no interaction with any implanted medical device. One magnetic audio frequency system interacted with 2 of 50 pacemakers. The acoustomagnetic system interacted with 48 of 50 pacemakers. Interactions included asynchronous pacing, atrial oversensing (producing "EAS induced tachycardia" in the ventricle), ventricular oversensing (with pacemaker inhibition), and paced beats resulting from the direct induction of current in the pacemaker ("EAS induced pacing"). These interactions produced symptoms in some patients ( palpitations, presyncopel only while patients were in the EAS field. No pacemaker was reprogrammed. We conclude that high energy, pulsed low frequency EAS systems such as acoustomagnetic systems interfere with most pacemakers. Pacemaker patients should be advised to minimize exposure to the fields of such systems to prevent the possibility of serious clinical events.