Your head or your heart: When the defibrillator turns off your brain chip

Our clinical cases are drawn from the case report literature. The stories, names, and patient details are fictional, however the narratives are based on published patient cases that are available in the references.

When Anthony* presented to the Emergency Department in cardiac arrest, the device in his head wasn't on anyone's mind. That evening Anthony has been sat at home watching the TV when he’d developed a racing in his chest and continuous palpitations. He had an underlying diagnosis of Heart Failure, for which an implanted cardiac defibrillator (ICD) had been implanted a few years earlier to help manage his heart rhythm [1]. On this particular evening the electrical activity of the heart had become increasingly erratic evolving into a life-threatening arrhythmia that prompted Anthony to seek emergency medical attention.

Anthony also had a past medical history of Parkinson’s disease, but there was little time to explore his medical background as he rapidly deteriorated on arrival to the hospital [1,2]. Once in the Emergency Department Anthony progressed into asystole and his heart stopped beating. The attending clinicians performed immediate life support, pumping Anthony with drugs, and providing electric shocks to restart the heart muscle. They were successful, Anthony's heart began to pump again and he was transferred to the Intensive Care Unit (ICU) to begin his recovery [1].

Yet the recovery took an unexpected course. When Anthony regained consciousness, he found himself struggling to speak, with a severe headache and a racing heart once more [1-2]. The medical team began investigating for the source of pathology, concerned that Anthony had developed a Stroke or perhaps an infection of the Central Nervous System (CNS) that was affecting his brain. The negative results that came back after all these tests confused the medical team who began exploring other avenues [2-3].

They sought the help of a Neurologist specialised in Parkinson's disease, in the hope that they could provide further insights on Anthony's deteriorating neurological state. The Neurologist quickly asked the team whether they had analysed Anthony's Deep Brain Stimulator (DBS), a device that had been implanted five years earlier to provide relief from his progressive parkinsonian symptoms. The DBS device consisted of a small neurostimulator situated into the chest which connected to electrodes in the brain that delivered a therapeutic electrical current to the anatomical site affected by the disease [3]. The presence of the electrodes can be seen on CT Imaging demonstrated in Figure 1, however the presence of the hardware can distort the image precluding the effective evaluation of brain tissue.

Figure 1: CT images demonstrating the position of the deep brain stimulator (DBS) wires in the brain [2]

The team began examining the remote control of the DBS device, from which they could see an error message indicating an incorrect configuration [2]. Unfortunately for Anthony, the specialist hospital that managed DBS devices was over 100 miles away in London and they currently had no beds available to transfer the patient [2]. Anthony was beginning to deteriorate further; the tachycardia was placing an increasing stress on his already damaged heart, and it was becoming apparent that the attending medical team did not have the required expertise to assist him [2-3].

In the end it took two days for a computer programmer equipped in configuring implanted devices to attend to Anthony and reinstate his voltage settings - a treatment that immediately resolved his symptoms [2]. In the meantime, the physicians had done their best to control Anthony's heart with a series of cardiac drugs and symptomatic management, however these had had a limited effect on symptom control as the source hardware issue remained untreated.

Once Anthony was feeling better, he was keen to understand the cause of his DBS failure, for it seemed very unlucky that both his heart and head should have malfunctioned on the same day. The engineer who had attended to Anthony described a range of possible sources of Electromagnetic (EM) radiation that could have interfered with his brain device, from hairdryers to airport security gates [2-5]. Anthony hadn't travel abroad recently and was not one to use a hairdryer, but given he was still experiencing pain from the site of the cardiac defibrillation he suspected the large electric current that had been shocked into his body may have had something to do with it. Unsurprisingly, he was right [1].

Anthony’s story is based on three case reports that describe complications resulting from malfunctioning deep brain stimulators (DBS). Davis and Zachary published the case of a patient with a DBS system in place that malfunctioned following cardiac defibrillation performed due to cardiac arrest [1]. Their description of this emergency medical scenario highlights that sometimes EM interference is unavoidable when saving a patient’s life, and hence device functions may need to be hierarchically prioritised based on the clinical context. The symptoms Anthony developed following the device malfunction were drawn from the case reported by Davis and Zachary, and two additional reports that described neurological symptoms in one case of DBS failure, and a fever and tachycardia in another [2-3]. In the report from Straw and Collaegues, the researchers described the range of symptoms that can manifest due to DBS errors and the challenge of treating these hardware malfunctions when the required engineering expertise is not always available.

Patients like Anthony who have two or more devices are becoming more common, and the concurrent presence of these co-existing technologies may heighten risk of disease due to the potential interaction of these tools. Several researchers have examined the challenges of device-device interactions and attempted to develop methodologies for addressing interactions that result in patient harm. In a further case report from Duncker and colleagues, the researchers describe the challenge of interactions between left ventricular assist devices (LVAD) and ICD systems that impaired wireless device communication for these patients [5]. The clinicians attempted a series of methods to minimise the interference, including “pseudo Faraday cage”, pan methods and different body positions and superextension of the arm (Figure 2 below) [5].

Figure 2: Initialization of handshake between programmer and device by (1) upright body position, (2) superextension of the arm, (3) “pan method” establishing a pseudo Faraday cage above the LVAD [Figure taken from case report reference [5]].

These cases highlight the important of considering sources of technology that may interfere with a medical device and remaining vigilant to the fact that the healthcare technology that clinicians deploy my also cause interference. Even seemingly simple healthcare technologies may affect devices, such as the interaction that can occur between ECGs and neurostimulators [6]. In order to provide appropriate care for these patients, individual clinicians need to be trained, but hospital protocols and guidelines also need to be updated to account for these potential harms. In the case of Anthony who required immediate life support, device-device interactions are not currently present in Advanced Life Support training for physicians but may be an important addition as we begin to see more patients with co-existing medical devices.

References

[1] Davis G, Levine Z. Deep Brain Stimulation Generator Failure due to External Defibrillation in a Patient with Essential Tremor. Stereotact Funct Neurosurg. 2021;99(1):38-39. doi: 10.1159/000510122. Epub 2020 Oct 16. PMID: 33070142.

[2] Straw I. et al. ‘When Brain Devices Go Wrong: A Patient with a Malfunctioning Deep Brain Stimulator (DBS) Presents to the Emergency Department’. BMJ Case Reports CP, vol. 15, no. 12, Dec. 2022

[3] A Jehad, et al. ‘Malignant Deep Brain Stimulator Withdrawal Syndrome’. BMJ Case Reports, vol. 12, no. 5, May 2019, p. e229122. PubMed, https://doi.org/10.1136/bcr-2018-229122.

[4] Youngerman B, et al. ‘A Decade of Emerging Indications: Deep Brain Stimulation in the United States’. Journal of Neurosurgery, vol. 125, no. 2, Aug. 2016, pp. 461–71. PubMed, https://doi.org/10.3171/2015.7.JNS142599.

[5] Duncker D, König T, Müller-Leisse J, Michalski R, Oswald H, Schmitto JD, et al. Electric smog: telemetry interference between ICD and LVAD. Herzschrittmachertherapie Elektrophysiologie. 2017 Sep 1;28(3):257–9.

[6] Mruk, Melanie, et al. ‘Neurostimulator-Induced ECG Artefacts: A Systematic Analysis’. Clinical Neurology and Neurosurgery, vol. 203, Apr. 2021, p. 106557. PubMed, https://doi.org/10.1016/j.clineuro.2021.106557.