Interference in implanted cardiac devices, part II

Epidural spinal cord recordings (ESRs): sources of neural-appearing artifact in stimulation evoked compound action potentials

Objective. Evoked compound action potentials (ECAPs) measured during epidural spinal cord stimulation (SCS) can help elucidate fundamental mechanisms for the treatment of pain and inform closed-loop control of SCS. Previous studies have used ECAPs to characterize neural responses to various neuromodulation therapies and have demonstrated that ECAPs are highly prone to multiple sources of artifact, including post-stimulus pulse capacitive artifact, electromyography (EMG) bleed-through, and motion artifact. However, a thorough characterization has yet to be performed for how these sources of artifact may contaminate recordings within the temporal window commonly used to determine activation of A-beta fibers in a large animal model.Approach. We characterized sources of artifacts that can contaminate the recording of ECAPs in an epidural SCS swine model using the Abbott Octrode™ lead.Main results. Spinal ECAP recordings can be contaminated by capacitive artifact, short latency EMG from nearby muscles of the back, and motion artifact. The capacitive artifact can appear nearly identical in duration and waveshape to evoked A-beta responses. EMG bleed-through can have phase shifts across the electrode array, similar to the phase shift anticipated by propagation of an evoked A-beta fiber response. The short latency EMG is often evident at currents similar to those needed to activate A-beta fibers associated with the treatment of pain. Changes in CSF between the cord and dura, and motion induced during breathing created a cyclic oscillation in all evoked components of recorded ECAPs.Significance. Controls must be implemented to separate neural signal from sources of artifact in SCS ECAPs. We suggest experimental procedures and reporting requirements necessary to disambiguate underlying neural response from these confounds. These data are important to better understand the framework for epidural spinal recordings (ESRs), with components such as ECAPs, EMG, and artifacts, and have important implications for closed-loop control algorithms to account for transient motion such as postural changes and cough.

Perioperative management of patients with cardiac implantable electronic devices

The use of cardiac implantable electronic devices (CIEDs) has increased significantly in recent years. Consequently, more patients with CIEDs will undergo surgery during their lifetime, and thus the involvement of anesthesiologists in the perioperative management of CIEDs is increasing. With ongoing advancements in technology, many types of CIEDs have been developed, including permanent pacemakers, leadless pacemakers, implantable cardioverter defibrillators, cardiac resynchronization therapy-pacemakers/defibrillators, and implantable loop recorders. The functioning of CIEDs exposed to an electromagnetic field can be affected by electromagnetic interference, potential sources of which can be found in the operating room. Thus, to prevent potential adverse events caused by electromagnetic interference in the operating room, anesthesiologists must have knowledge of CIEDs and be able to identify each type. This review focuses on the perioperative management of patients with CIEDs, including indications for CIED implantation to determine the baseline cardiovascular status of patients; concerns associated with CIEDs before and during surgery; perioperative management of CIEDs, including magnet application and device reprogramming; and additional perioperative provisions for patients with CIEDs. As issues such as variations in programming capabilities and responses to magnet application according to device can be challenging, this review provides essential information for the safe perioperative management of patients with CIEDs.

Nanoparticles Targeting the Molecular Pathways of Heart Remodeling and Regeneration

Cardiovascular diseases are the main cause of death worldwide, a trend that will continue to grow over the next decade. The heart consists of a complex cellular network based mainly on cardiomyocytes, but also on endothelial cells, smooth muscle cells, fibroblasts, and pericytes, which closely communicate through paracrine factors and direct contact. These interactions serve as valuable targets in understanding the phenomenon of heart remodeling and regeneration. The advances in nanomedicine in the controlled delivery of active pharmacological agents are remarkable and may provide substantial contribution to the treatment of heart diseases. This review aims to summarize the main mechanisms involved in cardiac remodeling and regeneration and how they have been applied in nanomedicine.

A case report of lead dysfunction presenting as high ventricular premature complex burden

Pacemaker-troubleshooting is an important step in the evaluation of a patient with syncope post-pacemaker-implantation. The basic functions of sensing, pacing and impedance may remain spuriously normal in the case of lead-microfracture or insulation break. We report a case in which the lead dysfunction was diagnosed based on multiple episodes of premature ventricular beats.

Repeated TACE in HCC after Fontan surgery and situs viscerum inversus: A case report

We describe the case of a 32-year-old man who developed a liver neoplasm due to previous Fontan surgery (FS) for a single ventricle anomaly and situs viscerum inversus. He was admitted to our hospital for suspected hepatocellular carcinoma during an Ultrasound (US) follow up. Computed tomography (CT) showed features of chronic liver disease and 7 cm hepatic nodule with arterial enhancement. Laboratory analyses documented preserved liver function and increased levels of alpha-fetoprotein. Trans-arterial-chemoembolization (TACE) was performed obtaining complete necrosis at 4 weeks of follow up and significant reduction of alpha-fetoprotein. The patient is currently in follow-up, being evaluated for further treatments and/or combined liver-heart transplantation. TACE is a therapeutic option for the treatment of patients with unresectable hepatocellular carcinoma (HCC) and with severe heart disease, like those submitted to FS and with also other vascular abnormalities like those correlated to situs viscerum inversus.

An operational approach to the execution of MR examinations in patients with CIED

In the context of the increasing spread of cardiac active implantable heart devices (CIEDs) in the population and of the wide diagnostic/therapeutic utility of magnetic resonance (MRI) examinations, the goal of this paper is to provide the experience of the Santa Maria Nuova Hospital of the USL Tuscany Center in Florence and to report an organizational proposal to perform, in the hospital settings, MRI examinations on patients carrying CIED. This report is intended to show the operational choices of a Radiology Department which organizes this activity in accordance with the new Italian regulatory framework in the field of safety of MR sites (Ministero della Salute in Decreto Ministeriale 10 agosto 2018 Determinazione degli standard di sicurezza e impiego per le apparecchiature a risonanza magnetica, 2018).

Recommendations for Perioperative Management of Patients with Cardiac Implantable Electronic Devices

SUMMARY – Four thousand cardiac implantable electronic devices (CIED) are implanted yearly in Croatia with constant increase. General anesthesia and surgery carry some specific risk for the patients with implanted CIEDs. Since most of the surgical procedures are performed in institutions without reprogramming devices available, or in the periods when they are unavailable, these guidelines aim to standardize the protocol for perioperative management of these patients. With this protocol, most of the procedures can be performed easily and, more importantly, safely in the majority of surgical patients.

Appropriate Classification and Filtering of Electromagnetic Interference by the S-ICD Sensing Algorithm During Surgery

The subcutaneous implantable cardioverter defibrillator (S-ICD) is a new device used for the prevention of sudden cardiac death. Best practices in the perioperative management of the S-ICD are not established; therefore, clinicians typically deactivate the device during surgery, with reinterrogation and activation postoperatively. This could put the patient at risk for being discharged with the device "off." We present two cases where electromagnetic interference was appropriately detected by the S-ICD and filtered. These cases present an important clinical finding that could lead to less deactivation of devices during surgery. Further research will be required to define which surgical procedures require magnet, reprogramming, or no changes.

Cardiac Pacemakers: Function, Troubleshooting, and Management: Part 1 of a 2-Part Series

Advances in cardiac surgery toward the mid-20th century created a need for an artificial means of stimulating the heart muscle. Initially developed as large external devices, technological advances resulted in miniaturization of electronic circuitry and eventually the development of totally implantable devices. These advances continue to date, with the recent introduction of leadless pacemakers. In this first part of a 2-part review, we describe indications, implant-related complications, basic function/programming, common pacemaker-related issues, and remote monitoring, which are relevant to the practicing cardiologist. We provide an overview of magnetic resonance imaging and perioperative management among patients with cardiac pacemakers.

Risk of electromagnetic interference induced by dental equipment on cardiac implantable electrical devices

Patients with cardiac implantable electrical devices should take special precautions when exposed to electromagnetic fields. Proximity to equipment used in clinical dentistry may cause interference. This study evaluated in vitro the risks associated with different types/makes of cardiac devices and types of dental equipment. Six electronic dental tools were tested on three implantable cardioverter defibrillators and three pacemakers made by different manufacturers. Overall, the risk of interference with the pacemakers was 37% lower than with the implantable cardioverter defibrillators. Regarding the types/makes of cardiac devices analysed, that from Boston Scientific had a five-fold greater risk of interference than did that from Biotronik [prevalence ratio (PR) = 5.58]; there was no difference between that from Biotronik and that from Medtronic. Among the dental equipment, the electric pulp tester had the greatest risk of inducing interference and therefore this device was used as the benchmark. The electronic apex locator (PR = 0.29), Periotest M (PR = 0.47), and the ultrasonic dental scaler (PR = 0.59) were less likely to induce interference than the electric pulp tester. The risk was lowest with the electronic apex locator. Pacemakers presented a lower risk of light to moderate interference (PR = 0.63). However, the risk of severe electromagnetic interference was 3.5 times higher with pacemakers than with implantable cardioverter defibrillators (PR = 3.47).

Do we need to establish guidelines for patients with neuromodulation implantable devices, including spinal cord stimulators undergoing nonspinal surgeries?

Background:

Spinal cord stimulation is currently approved to treat chronic intractable pain of the trunk and limbs. However, such implantable electronic devices are vulnerable to external electrical currents and magnetic fields. Within the hospitals and modern operating rooms (ORs), there is an abundance of electrical devices and other types of equipment that could interfere with such devices. Despite the increasing number of patients with neuromodulation implantable devices, there are no written guidelines available or consensus of cautions for such patients undergoing unrelated surgery.

Case Descriptions:

A 60-year-old female with a permanent St. Jude's spinal cord stimulator (SCS) presented for open total abdominal hysterectomy. Both the anesthesia and gynecology staffs were aware of the device presence, but were unaware of any precautions regarding intraoperative management. The device was found to be nonmagnetic resonance imaging compatible, and bipolar cautery was used instead of monopolar cautery. A 59-year-old female with a 9-year-old permanent Medtronic SCS, presented for right total hip arthroplasty. The device was switched off prior to entering the OR, bipolar cautery was used, and grounding pads were placed away from her battery site. In each case, the manufacturer's representative was contacted preoperative. Both surgeries proceeded uneventfully.

Conclusions:

The Food and Drug Administration safety information manual warns about the use of diathermy, concomitant implanted stimulation devices, lithotripsy, external defibrillation, radiation therapy, ultrasonic scanning, and high-output ultrasound, all of which can lead to permanent implant damage if not turned off prior to undertaking procedures. Lack of uniform guidelines makes intraoperative management, as well as remote anesthesia care of patients with previously implanted SCSs unsafe.

Radiotherapy in patients with pacemakers and implantable cardioverter defibrillators: a literature review

An increasing number of patients with implantable cardiac rhythm devices undergo radiotherapy (RT) for cancer and are thereby exposed to the risk of device failure. Current safety recommendations seem to have limitations by not accounting for the risk of pacemakers and implantable cardioverter defibrillators malfunctioning at low radiation doses. Besides scant knowledge about optimal safety measures, only little is known about the exact prevalence of patients with devices undergoing RT. In this review, we provide a short overview of the principles of RT and present the current evidence on the predictors and mechanisms of device malfunctions during RT. We also summarize practical recommendations from recent publications and from the industry. Strongly associated with beam energy of photon RT, device malfunctions occur at ∼3% of RT courses, posing a substantial issue in clinical practice. Malfunctions described in the literature typically consist of transient software disturbances and only seldom manifest as a permanent damage of the device. Through close cooperation between cardiologists and oncologists, a tailored individualized approach might be necessary in this patient group in waiting time for updated international guidelines in the field.

Capacity of dental equipment to interfere with cardiac implantable electrical devices

Patients with cardiac implantable electrical devices should take precautions when exposed to electromagnetic fields. Possible interference as a result of proximity to electromagnets or electricity flow from electronic tools employed in clinical odontology remains controversial. The objective of this study was to examine in vitro the capacity of dental equipment to provoke electromagnetic interference in pacemakers and implantable cardioverter defibrillators. Six electronic dental instruments were tested on three implantable cardioverter defibrillators and three pacemakers from different manufacturers. A simulator model, submerged in physiological saline, with elements that reproduced life-size anatomic structures was used. The instruments were analyzed at differing distances and for different time periods of application. The dental instruments studied displayed significant differences in their capacity to trigger electromagnetic interference. Significant differences in the quantity of registered interference were observed with respect to the variables manufacturer, type of cardiac implant, and application distance but not with the variable time of application. The electronic dental equipment tested at a clinical application distance (20 cm) provoked only slight interference in the pacemakers and implantable cardioverter defibrillators employed, irrespective of manufacturer.

Magnetic resonance imaging in patients with a subcutaneous implantable cardioverter-defibrillator

Aims

Our aim was to evaluate the potential for safely imaging patients with a new type of implantable cardioverter-defibrillator called the subcutaneous implantable cardioverter-defibrillator (S-ICD) in a 1.5 T magnetic resonance imaging (MRI) scanner. With the increasing number of patients with cardiac implantable devices who are indicated for MRI, there is a growing need for establishing MRI compatibility of cardiac implantable devices.

Methods and Results

Patients with implanted S-ICD systems underwent one or more types of anatomical MRI scans. The S-ICD was programmed off and patients were monitored throughout the imaging procedure. Device function was evaluated pre- and post-scan. Patients were asked to report immediately any pain, torqueing movement, or heating sensation in the area of the pocket or electrode. Fifteen patients underwent a total of 22 examinations at 1.5 T. Scans included brain, spine, knee, and heart. Two patients were re-scanned due to complaints of heating over the can during lumbar scans, which was caused by a thermistor probe placed on the skin to measure skin temperature. All the remaining scans occurred without incident. No evidence of device malfunction was observed.

Conclusion

This study is the first to domonstrate the feasibility of exposing S-ICD patients to MRI using the scanning and monitoring protocol described. More data are required to support S-ICD as a MRI conditional device.

Interference between dental electrical devices and pacemakers or defibrillators: results from a prospective clinical study

BACKGROUND

The authors aimed to determine whether electrical dental devices would interfere with the function of cardiac pacemakers or implantable cardioverter defibrillators (ICDs) in humans.

METHODS

The authors exposed asymptomatic nonpacemaker-dependent patients to commonly used electrical dental equipment (for example, battery-operated curing lights, ultrasonic baths, ultrasonic scalers, electric pulp testers, and electric toothbrushes) in an outpatient cardiology clinic. The authors operated dental devices at various distances and programmed cardiac devices to sense and pace. The authors obtained cardiac tracings using a cardiac programming unit and a cardiac provider who noted any interference interpreted the results in real time.

RESULTS

The authors enrolled 32 consecutive patients and tested 12 pacemakers and 20 ICDs. They did not observe any significant clinical interference in sensing and pacing functions in any patient; however, they noted minor interference without clinical impact in the telemetry from the cardiac programming unit during use of the ultrasonic scaler and bath.

CONCLUSIONS

The findings of this prospective study suggest that electrical devices commonly used in dental practices do not interfere with the sensing and pacing of contemporary cardiac patients' pacemakers or ICDs. However, they do interfere with the telemetry from the cardiac programming unit, without any clinical impact on patient safety. These findings should help in the development of clinical guidelines regarding dental management of patients with pacemakers or ICDs.

PRACTICAL IMPLICATIONS

Electrical dental devices (for example, ultrasonic baths, ultrasonic scalers) induced minor interference with programmers that interrogate cardiac devices implanted in patients; however, overall, dental devices do not appear to interfere with pacemakers' and defibrillators' pacing and sensing function.

Correlation of geomagnetic activity with implantable cardioverter defibrillator shocks and antitachycardia pacing

OBJECTIVE

To investigate a potential relationship between implantable cardioverter defibrillator (ICD) therapies and daily geomagnetic activity (GMA) recorded in a large database.

PATIENTS AND METHODS

The ALTITUDE database, derived from the Boston Scientific LATITUDE remote monitoring system, was retrospectively analyzed for the frequency of ICD therapies. Daily GMA was expressed as the planetary K-index and the integrated A-index and was graded as levels I (quiet), II (unsettled), III (active), and IV (storm).

RESULTS

A daily mean ± SD of 59,468±11,397 patients were monitored between January 1, 2009, and May 15, 2012. The distribution of days according to GMA was as follows: level I, 924/1231 (75%); level II, 226/1231 (18%); level III, 60/1231 (5%); and level IV, 21/1231 (2%). The daily mean ± SD numbers of ICD shocks received per 1000 active patients in the database were 1.29±0.47, 1.17±0.46, 1.03±0.37, and 0.94±0.29 on level I, II, III, and IV days, respectively; the daily mean ± SD sums of shocks and antitachycardia pacing therapies were 9.29±2.86, 8.46±2.45, 7.92±1.80, and 7.83±2.28 on quiet, unsettled, active, and storm days, respectively. A significant inverse relationship between GMA and frequency of ICD therapies was identified, with the most pronounced difference between level I and level IV days (P<.001 for shocks; P=.008 for shocks + antitachycardia pacing).

CONCLUSION

In a large-scale cohort analysis, ICD therapies were delivered less frequently on days of higher GMA, confirming the previous pilot data and suggesting that higher GMA does not pose an increased risk of arrhythmias using ICD therapies as a surrogate marker. Further studies are needed to gain an in-depth understanding of the underlying mechanisms.

Republished: Cardiac MRI of patients with implanted electrical cardiac devices

Implantable pulse generators and defibrillators have traditionally been considered contraindications to MRI. However, recent data have challenged this paradigm and demonstrated that patients with newer generation devices can safely undergo MRI, including cardiac MRI, provided basic precautions are taken. Indeed, the introduction of MRI conditional systems has led to a conceptual shift in clinical decision making-'can this patient undergo MRI safely?' is being superseded by 'should this patient be implanted with an MRI conditional device?'. This review outlines the risks associated with MRI in patients with implanted cardiac devices, and discusses practical measures to minimise risks and facilitate safe and diagnostic scanning.

Frequent Home Monitoring of ICD Is Effective to Prevent Inappropriate Defibrillator Shock Delivery

Recently, in the context of telemedicine, telemonitoring services are gaining attention. They are offered, for example, to patients with implantable cardioverter defibrillators (ICDs). A major problem associated with ICD therapy is the occurrence of inappropriate shocks which impair patients' quality of life and may also be arrhythmogenic. The telemonitoring can provide a valid support to intensify followup visits, in order to improve the prevention of inappropriate defibrillator shock, thus enhancing patient safety. Inappropriate shock generally depends on atrial fibrillation, supraventricular tachycardia, and abnormal sensing (such as those caused by electromagnetic interferences). As a practical example, an unusual case of an ICD patient who risked an inappropriate shock while taking a shower is reported. Continuous remote telemonitoring was able to timely warn cardiologist via GSM-SMS, who were able to detect improper sensing examining the intracardiac electrogram via Web. Patient was promptly contacted and warned to not further come in contact with the hydraulic system and any electrical appliance to prevent an inappropriate defibrillator shock. This demonstrates the effectiveness and usefulness of continuous remote telemonitoring in supporting ICD patients.

Do ultrasonic dental scalers interfere with implantable cardioverter defibrillators? An in vivo investigation

OBJECTIVES

To test the in vivo effects of an ultrasonic dental scaler on various implanted cardioverter defibrillator (ICD) models.

METHODS

12 consecutive patients with ICDs had continuous both electrocardiogram monitoring and device interrogation to detect interferences during the use of an ultrasonic dental scaler.

RESULTS

No interferences were detected by any ICD. Evaluation of the electrocardiograms for each patient failed to show any abnormalities in pacing during testing.

CONCLUSION

The results of this study suggest that the routinary clinic use of piezoelectric dental scalers do not interfere with the functioning of any of the tested ICDs.

CLINICAL SIGNIFICANCE

Ultrasonic dental scalers have been suspected of electromagnetic interference (EMI) with the normal functioning of ICDs and the use of this type of equipment for patients with these devices has been controversial. This is the first in vivo study to investigate EMI of ICD activity during the operation with ultrasonic dental scaler.

Cardiac pacemakers and electrocautery in ophthalmic surgery

The aging of the population and our ability to care for a patient with increasingly complex disease suggest that we will be caring for many more patients with pacemakers and implantable cardioverter-defibrillators. Using surgical diathermy or electrocautery on these patientscan present the additional risk of electrical interference and appropriate precautions need to be considered. We summarise the different type of pacemakers and electrocautery, and how electrocautery can interfere with such devices. We discuss the relevant issues that should be considered when these patients undergo assessment for surgery and their intra- and post-operative management, including the use of magnets.

Cardiac CT: Imaging of and Through Cardiac Devices

For patients with cardiac devices, cardiac computed tomography (CT) remains the mainstay for imaging due to its superior resolution as compared with echocardiography and nuclear studies and no contraindication to metal as with cardiac magnetic resonance imaging. This review focuses on the evaluation and pitfalls of coronary arterial imaging in patients with devices, such as pacemakers, implantable defibrillators, cardiac resynchronization therapy (CRT), as well as complications such as lead perforation and safety concerns of CT interference. We discuss both pre- and post-procedural CRT assessment for coronary venous imaging and pre-procedural myocardial scar assessment to localize regions of scar and peri-infarct zone to facilitate ventricular tachycardia ablation in patients with devices. We describe potential new research on dyssynchrony and integration with myocardial scar and site of latest activation for patients with or being considered for CRT. We detail the utility of CT for the assessment of proper function and complications in patients with left ventricular assist device implantation.

Endoscopy and implantable electronic devices

The increasing use of implantable electronic devices such as cardiac pacemakers and neurostimulators means that they are being increasingly encountered in endoscopy departments. The electromagnetic fields generated during electrosurgery and with magnetic imaging systems have the potential to interfere with such devices. The authors present a case that highlights some of the steps necessary for minimising risk, review the evidence and summarise the currently available guidance.

[Pacemaker, implanted cardiac defibrillator and irradiation: Management proposal in 2010 depending on the type of cardiac stimulator and prognosis and location of cancer]

Ionizing radiation may interfere with electric components of pacemakers or implantable cardioverter-defibrillators. The type, severity and extent of radiation damage to pacemakers, have previously been shown to depend on the total dose and dose rate. Over 300,000 new cancer cases are treated yearly in France, among which 60% are irradiated in the course of their disease. One among 400 of these patients has an implanted pacemaker or defibrillator. The incidence of pacemaker and implanted cardioverter defribillator increases in an ageing population. The oncologic prognosis must be weighted against the cardiologic prognosis in a multidisciplinary and transversal setting. Innovative irradiation techniques and technological sophistications of pacemakers and implantable cardioverter-defibrillators (with the introduction of more radiosensitive complementary metal-oxide-semiconductors since 1970) have potentially changed the tolerance profiles. This review of the literature studied the geometric, dosimetric and radiobiological characteristics of the radiation beams for high energy photons, stereotactic irradiation, protontherapy. Standardized protocols and radiotherapy optimization (particle, treatment fields, energy) are advisable in order to improve patient management during radiotherapy and prolonged monitoring is necessary following radiation therapy. The dose received at the pacemaker/heart should be calculated. The threshold for the cumulated dose to the pacemaker/implantable cardioverter-defibrillator (2 to 5 Gy depending on the brand), the necessity to remove/displace the device based on the dose-volume histogram on dosimetry, as well as the use of lead shielding and magnet are discussed.

50th Anniversary of the first successful permanent pacemaker implantation in the United States: historical review and future directions

June 2010 marks the 50th anniversary of the first successful human cardiac pacemaker implantation in the United States. On June 6, 1960, in Buffalo, New York, Dr. William Chardack implanted a pacemaker, designed and built by Wilson Greatbatch, an electrical engineer and inventor, in a 77-year old man with complete atrioventricular block, extending the patient's life by 18 months. This landmark event ushered in a new era of implantable cardiac pacemakers with batteries and leads of high reliability and increasing durability. Over the past half century, the field of electrophysiology and implantable devices for the management of cardiac conduction disturbances has evolved dramatically. Today's pacemakers include increasingly complex features such as telemetry monitoring, auto programmability, and hemodynamic sensors. New-generation leads present a sophisticated design with improved geometry and steroid-eluting tips to reduce chronic inflammation, maintaining a low pacing threshold and high sensing capability. The lithium iodide battery remains the mainstay of implantable pacemaker systems, exhibiting a multiple-year lifespan, slow terminal decay, and a reduced size and cost of production. Although Greatbatch's first successful pacemaker implantation remains a seminal scientific contribution to modern cardiovascular disease management, emerging developments in this field may challenge its preeminence. Important challenges such as imaging compatibility, lead durability, and infection prevention are being addressed. Novel concepts such as leadless and biologic pacing are under active investigation. In conclusion, Greatbatch's historic achievement 50 years ago reminds us that technologic progress is timeless, as efforts to enhance clinical outcomes and the quality of life continue unimpeded into the 21st century.

Interference of remote magnetic catheter navigation and ablation with implanted devices for pacing and defibrillation

AIMS

Remote magnetic catheter navigation (RMN) may facilitate catheter ablation. However, as the system uses permanent magnets, interference (INF) with devices for pacing [pacemaker (PM)], defibrillation [implantable cardioverter defibrillators (ICD)], or cardiac resynchronisation [cardiac resynchronization therapy (CRT)] may occur. We investigated the effects of the RMN system on implanted arrhythmia devices in a prospective series.

METHODS AND RESULTS

Prior to RMN-guided electrophysiological procedures, devices were fully interrogated and programmed to VVI 40/min with tachycardia detection off (if applicable). Periprocedural device performance was monitored by 12-lead electrocardiogram, and duration and effect of asynchronous stimulation resulting from INF were evaluated. Following the procedure, devices were again interrogated and system integrity verified. A total of 21 procedures in 18 patients with implanted devices [PM n = 12, ICD n = 3, CRT-pacemaker (P) n = 1, CRT-defibrillation (D) n = 2] were evaluated. No relevant changes in lead parameters or device programming were observed after the procedure. No INF was noted in ICD/CRT-D devices (tachycardia detection off) and in 2 PMs, whereas 10 PMs and 1 CRT-P switched to asynchronous stimulation for 1.8 ± 0.3 h (63 ± 13% of RMN duration) without clinical adverse effects. In one patient, ventricular tachycardia (VT) degenerating in ventricular fibrillation occurred, but no causal relation between INF and VT initiation could be ascertained.

CONCLUSION

This prospective data provide no evidence that using RMN in patients with implanted arrhythmia devices may cause persistent device dysfunction. Asynchronous PM stimulation is common without negative clinical consequences. Although a causal role of INF for the VT observed seems unlikely, risks and benefits of RMN utilization should carefully be weighed for each patient with an implanted arrhythmia device.