Inappropriate implantable cardioverter-defibrillator discharges unrelated to supraventricular tachyarrhythmias

An uncommon cause of inappropriate ICD shock

In cases of electromagnetic interference (EMI), if the source of the inappropriate EMI cannot be identified, then the sensitivity of the device could be decreased, or the cycle length of the VF detection trigger zone changed.

Incidence of magnet mode in patients with implantable cardioverter defibrillators

PURPOSE

To determine the current incidence of antitachycardia therapy suspension due to magnet reversion in patients with implantable cardioverter defibrillators (ICDs).

METHODS

From March 2012 to September 2018, all St. Jude Medical ICD interrogations performed at the Deutsches Herzzentrum München were screened for stored events of antitachycardia therapy suspension caused by static magnetic fields (flux densities ≥ 1 mT as defined in St. Jude Medical ICDs) affecting the giant magnetoresistance (GMR) sensor. Intentional ICD deactivation or inappropriate magnet application in the hospital was classified as non-environmental electromagnetic interference (EMI) whereas in the case of any other stored magnet reversion, the event was classified as presumably environmental EMI.

RESULTS

Data from 201 St. Jude Medical ICD patients (mean age 62 ± 24 years, 165 males/36 females) were included in the analysis. ICD interrogations occurred at a mean follow-up of 25.1 months ± 15.6 months and summed up to a total of 464 patient-years of follow-up. A total number of 43 magnet reversion events were detected in 21 patients. Thirty-two events in 13 patients were presumably related to environmental EMI sources. Suspension of antitachycardia therapy only occurred in a temporary fashion. None of the patients experienced any ventricular tachyarrhythmia during ICD inhibition. The incidence of antitachycardia therapy suspension due to magnet reversion related to presumably environmental EMI sources was 6.9% per patient and year.

CONCLUSION

Although none of the patients experienced any harmful event, antitachycardia therapy suspension due to magnet reversion is a common issue. Patients should be well-educated about potential EMI sources as well as trained in handling them.

Cautery selection for oculofacial plastic surgery in patients with implantable electronic devices

PURPOSE

To discover oculofacial plastic surgeon practice patterns for cautery selection in the setting of implantable electronic devices and present guidelines based on a review of current literature.

METHODS

A 10-Question web-based survey was sent to the email list serve of the American Society of Ophthalmic Plastic and Reconstructive Surgery to determine surgeon cautery preference in the setting of various implantable electronic devices and comfort level with the guidelines for cautery selection in their practice or institution. The relationship between survey questions was assessed for statistical significance using Pearson's Chi-square tests.

RESULTS

Two hundred ninety-three (41% response rate) surveys were completed and included for analysis. Greater than half of respondents either had no policy (36%) or were unaware of a policy (19%) in their practice or institution regarding cautery selection in patients with a cardiac implantable electronic device. Bipolar cautery was favored for use in patients with a cardiac implantable electronic device (79%-80%) and this number dropped in patients with implantable neurostimulators (30%). Overall, one-third of respondents did not feel comfortable with their practice/institution policy.

CONCLUSION

Choices and comfort level among oculofacial plastic surgeons for cautery selection in patients with implantable electronic devices vary considerably, and some choices may increase the risk for interference-related complications. Practice patterns vary significantly in the setting of a neurostimulator or cochlear implant, where interference can cause thermal injury to the brain and implant damage, respectively. Guidelines are proposed for cautery selection in patients with implantable electronic devices undergoing oculofacial plastic surgery.

Multiple inappropriate implantable cardiac defibrillator therapies in rapid succession

Inappropriate implantable cardiac defibrillator (ICD) shocks are associated with significant morbidity and have the potential to trigger ventricular arrhythmias, cardiac decompensation, and death. We present a case of multiple inappropriate ICD therapies in rapid succession due electromagnetic interference from a Dr‐Ho's transcutaneous electric nerve stimulator machine, and subsequently from a faulty electrical outlet.

Long-term incidence of inappropriate shocks in patients with implantable cardioverter defibrillators in clinical practice-an underestimated complication?

BACKGROUND

Implantable cardioverter defibrillators (ICD) are life-saving device therapy, and patients often carry devices for decades with interim pulse generator exchanges. Inappropriate shocks are associated with impaired quality of life and increased mortality, but available data on their incidence and etiology outside of clinical trials is limited and usually restricted to the lifespan of a singular device. We hypothesized that the incidence in clinical practice is underestimated and aimed this study to retrospectively assess the long-term incidence and etiology of inappropriate shocks in a real-world cohort of patients with multiple ICDs over a long follow-up period.

METHODS

Patients with ICDs implanted between 1998 and 2012 in two Swiss cardiology departments and at least one device exchange in the same department thereafter were included in this cohort. Retrospective analysis with follow-up until 2016 was conducted to assess incidence and etiology of inappropriate ICD shocks.

RESULTS

Two hundred forty-nine ICDs were implanted in 100 patients (mean age: 60.1 ± 11.7; 80% male). Over a mean follow-up time of 11.2 (± 3.6) years, 555 shocks occurred in 55 patients. One hundred twenty-three (22%) shocks in 23 (23%) patients were inappropriate. Supraventricular arrhythmia and oversensing were the most frequent causes of inappropriate shock. Patients with younger age or previous supraventricular arrhythmias were at increased risk of inappropriate shocks. Patients with inappropriate shocks during the lifespan of their first ICD were at increased risk for inappropriate shocks in subsequent devices.

CONCLUSIONS

Inappropriate shocks are an underestimated and frequent problem in clinical practice with an incidence that may exceed numbers of previously reported clinical trials with shorter follow-up periods. Patients at increased risk for inappropriate shocks need careful evaluation of potential therapeutic optimization strategies including pharmacological treatment, device programming, electrophysiological ablation, device downgrading, and telemonitoring.

Electromagnetic Interference from Swimming Pool Generator Current Causing Inappropriate ICD Discharges

Electromagnetic interference (EMI) includes any electromagnetic field signal that can be detected by device circuitry, with potentially serious consequences: incorrect sensing, pacing, device mode switching, and defibrillation. This is a unique case of extracardiac EMI by alternating current leakage from a submerged motor used to recycle chlorinated water, resulting in false rhythm detection and inappropriate ICD discharge. A 31-year-old female with arrhythmogenic right ventricular cardiomyopathy and Medtronic dual-chamber ICD placement presented after several inappropriate ICD shocks at the public swimming pool. Patient had never received prior shocks and device was appropriate at all regular follow-ups. Intracardiac electrograms revealed unique, high-frequency signals at exactly 120 msec suggestive of EMI from a strong external source of alternating current. Electrical artifact was incorrectly sensed as a ventricular arrhythmia which resulted in discharge. ICD parameters including sensing, pacing thresholds, and impedance were all normal suggesting against device malfunction. With device failure and intracardiac sources excluded, EMI was therefore strongly suspected. Avoidance of EMI source brought complete resolution with no further inappropriate shocks. After exclusion of intracardiac interference, device malfunction, and abnormal settings, extracardiac etiologies such as EMI must be thoughtfully considered and excluded. Elimination of inappropriate shocks is to "first, do no harm."

Inappropriate ICD Discharge Related to Electrical Muscle Stimulation in Chiropractic Therapy: A Case Report

Implantable cardioverter defibrillators (ICDs) have been shown to reduce mortality in high-risk patients. Despite several advances in programming ICDs, inappropriate shocks persist and continue to be psychologically and physically disturbing. External electromagnetic interference from electrocautery, welding, acupunctures, low-output transcutaneous electric nerve stimulators, and electronic muscle stimulators may result in inappropriate ICD sensing and shock. We present a 63-year-old female who presented to the emergency department after an ICD shock while undergoing electronic muscle stimulation in chiropractic treatment, during which light electrical pulses were sent through skin electrodes. Our case highlights the importance of recognizing methods used by alternative medicine doctors, including electrical muscle stimulation that may cause electromagnetic interference and inappropriate ICD discharge and therefore, a higher overall mortality risk.

Chronic lead malposition diagnosis and management: discussion of two cases and literature review

Management of lead malposition is crucial to avoid complications and is carried out on case-by-case bases. The 12-lead ECG during pacing and chest X-ray are essential during initial workup and recommended for new patients to the device clinic. Echocardiography and CT scan are important to confirm the location and plan appropriate therapy.

Clinical management of electromagnetic interferences in patients with pacemakers and implantable cardioverter-defibrillators: review of the literature and focus on magnetic resonance conditional devices

The number of cardiac implantable electronic devices (CIEDs) has greatly increased in the last 10 years. Many electronic devices used in daily activities generate electromagnetic interferences (EMIs) that can interact with CIEDs. In clinical practice, it is very important to know the potential sources of EMIs and their effect on CIEDs in order to understand how to manage or mitigate them. A very important source of EMI is magnetic resonance (MR), which is considered nowadays the diagnostic gold standard for different anatomical districts. In this review, we focused on the effects of EMI on CIEDs and on the clinical management. Moreover, we made a clarification about MR and CIEDs.In patients with CIEDs, EMIs may cause potentially serious and even life-threatening complications (inappropriate shocks, device malfunctions, inhibition of pacing in pacemaker-dependent patients) and may rarely dictate device replacement. The association of inappropriate shocks with increased mortality highlights the importance of minimizing the occurrence of EMI. Adequate advice and recommendations about the correct management of EMIs in patients with CIEDs are required to avoid all complications during hospitalization and in daily life. Furthermore, the article focused on actual management about MR and CIEDs.

Shock whilst gardening--implantable defibrillators & lawn mowers

Electromagnetic interference with implantable cardioverter defibrillators (ICDs) can cause inappropriate shock delivery or temporary inhibition of ICD functions. We present a case of electromagnetic interference between a lawn mower and an ICD resulting in an inappropriate discharge of the device due to erroneous detection of ventricular fibrillation.

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.

Transient hyperkalemia-induced T-wave oversensing as a cause of inappropriate ICD discharges

The present case describes a patient with an implantable cardioverter-defibrillator (ICD) who reported several ICD inappropriate discharges due to transient T-wave oversensing in the setting of acute hyperkalemia. T-wave oversensing was detected only at telemetry interrogation while T-wave amplitude at surface 12-lead electrocardiogram was normal. Oversensing was abolished by reducing potassium levels and by device reprogramming. This case report underscores the importance of identifying a potentially reversible cause of ICD inappropriate discharges and the utility of careful review of stored electrograms. <Learning objective: This case report underscores the importance of understanding the diversity of causes of implantable cardioverter-defibrillator malfunctioning and the utility of careful review of stored electrograms.>.

Electromagnetic interference of automatic implantable cardioverter defibrillator and HeartWare left ventricular assist device

The use of continuous-flow left ventricular assist devices (LVAD) have markedly improved outcomes in patients with advanced heart failure (HF). The HeartWare LVAD is a miniaturized centrifugal pump implanted within the pericardial space. Implantable cardioverter-defibrillators (ICDs) are susceptible to oversensing of extracardiac signals (electromagnetic interference [EMI]). We report two cases of EMI in patients that received a HeartWare LVAD as destination therapy for advanced HF. The patients were 75 and 78 years old, both with severe ischemic dilated cardiomyopathy (ejection fraction < 0.20) and New York Heart Association class 4 heart failure. Both patients had a St. Jude Medical Unify ICD with a 7 Fr dual coil St. Jude Medical Durata ICD lead. In both patients, the lead location was in the right ventricular apex with an inferior orientation. Both patients experienced immediate ICD therapies after LVAD placement, requiring the tachytherapies to be disabled. ICD programming changes to increase sensitivity and the detection windows were ineffective. Both patients underwent ICD system revision. In one patient, the existing lead was moved to an anteroseptal location that stopped the EMI. In the other patient, the ICD system was changed to allow a separate right ventricular sensing lead in an anteroseptal location and a dual coil ICD lead placed in an apical location, a strategy used to obtain an acceptable defibrillation threshold. The patients have had no subsequent EMI detected on clinical and remote monitoring. Patients with a right ventricular apical ICD lead placement that undergo placement of a HeartWare LVAD are susceptible to EMI and inappropriate ICD therapies. These cases suggest the primary mechanism is proximity of the ICD lead to the device and as such relocation to an anteroseptal location can overcome the problem. These data suggest that all patients that receive a HeartWare LVAD with an ICD should have the device carefully checked at maximum LVAD output to determine if EMI may be present. ASAIO Journal 2013;59:136-139. Key Words: left ventricular assist device, electromagnetic interference, improper ICD shocks, end-stage heart failure.

Electromagnetic interference and implanted cardiac devices: the nonmedical environment (part I)

The number of patients with cardiovascular implantable electronic devices (CIEDs), such as permanent pacemakers and implantable cardioverter-defibrillators, is dramatically rising due to an aging population and recent clinical trials showing benefits in mortality and morbidity. Coupled with this increase in the number of patients with CIEDs is the proliferation of technology that emits electromagnetic signals, which can potentially interfere with CIED function through electromagnetic interference (EMI). Despite continuous efforts of manufacturers to create "EMI-proof" CIEDs, adverse events from EMI still occur. Physicians caring for patients with CIEDs should be aware of potential sources of EMI and appropriate management options. This 2-part review aims to provide a contemporary overview of the current knowledge regarding risks attributable to EMI interactions from the most common nonmedical (Part I) and medical (Part II) sources.

Inappropriate Implantable Cardioverter-Defibrillator Therapy

Although improvements in implantable cardioverter-defibrillator (ICD) therapy have taken place, many challenges do remain. Inappropriate delivery of therapy is a big problem that impacts the quality of life of ICD recipients. Although there is now a clear understanding that atrial arrhythmias are the main cause of inappropriate ICD therapies, physicians have not been very successful in preventing them. Additionally, although many tachycardia detection discriminators have been shown to be helpful, it is not clear that there is a particular combination that is ideal for all patients. Until such an algorithm is developed (which may not be possible), a detailed knowledge and use of all available programming options, guided by special characteristics of each unique patient, are the only foreseeable solutions. Finally, one must face the prospect that this problem cannot be vanquished, but only ameliorated.

Tools and strategies for the reduction of inappropriate implantable cardioverter defibrillator shocks

Implantable cardioverter defibrillators (ICDs) have been shown to provide a survival benefit in patients at high risk of sudden cardiac death. A major problem associated with ICD therapy is the occurrence of inappropriate shocks which impair patients' quality of life and may also be arrhythmogenic. Despite recent technological advances, the incidence of inappropriate shocks remains high, thus posing a challenge that we have to meet. In the present review we summarise the available tools and the strategies that can be followed in order to reduce inappropriate ICD shocks.

Risk of interference from transcutaneous electrical nerve stimulation on the sensing function of implantable defibrillators

BACKGROUND

The use of transcutaneous electrical nerve stimulation (TENS) for pain relief is increasing. At the same time the implantable cardioverter defibrillator (ICD) is a routine treatment for malignant tachyarrhythmias. Today patients often need devices for more than one condition, and consideration must be given to the interaction between them. We studied the risk of interference between TENS and the ICD function.

METHODS AND RESULTS

Thirty patients who had received an ICD underwent a test protocol including TENS at the mammilla and hip levels, at two energy levels, and at the highest comfortable stimulation level. The effects of TENS on the electrocardiogram lead II, intracardiac electrograms, and the ICD marker channels were analyzed. Disturbance from TENS on the sensing function was seen at all stimulation attempts. Interference between the systems was observed in 16 patients. In eight patients (27%) the interpretation was VT/VF and in 14 patients (47%) as ventricular premature extra beats. Other kinds of interactions were seen in five patients (16%). Each patient could have more than one kind of interference.

CONCLUSIONS

Noise reversion and undersensing might prevent the ICD from delivering shock when it should and the interpretation as VT/VF could result in inappropriate shocks. Because of the potentially serious consequences of interference we do not recommend the use of TENS in patients with ICD.

Electronic article surveillance systems and interactions with implantable cardiac devices: risk of adverse interactions in public and commercial spaces

Electronic article surveillance (EAS) systems are widely implemented in public spaces and can adversely affect the performance of pacemakers and implantable cardioverter defibrillators. The interaction between implantable devices and EAS systems is a serious problem that can be minimized through appropriate facility design. Careful facility design and employee education along with patient vigilance remain imperative in avoiding potentially life-threatening EAS system-implantable device interactions.