Troubleshooting electromagnetic interference in a patient with centrifugal flow left ventricular assist device and subcutaneous implantable cardioverter defibrillator

Abstract

A 25-year-old man with severe nonischemic dilated cardiomyopathy underwent subcutaneous implantable cardioverter defibrillator (S-ICD) implant and subsequently underwent HeartWare ventricular assist device (HVAD) placement. Postoperative interrogation revealed both primary and secondary S-ICD vectors inappropriately regarded sinus rhythm as "noise," and the alternate vector significantly undersensed sinus rhythm. The S-ICD was reinterrogated using high-resolution capture to visually confirm EMI with a dominant frequency in both the primary and secondary vectors of 46.67 Hz that fell within the S-ICD operational range of 9-60 Hz. The 46.67 Hz frequency correlated with the HVAD operational speed of 2,800 RPM. The HVAD pump speed was increased from 2,800 to 3,000 RPM, resulting in a dominant frequency of 50 Hz. The notch filter is nonprogrammable in S-ICDs. However, the built-in filter is 50 Hz for countries in European time zones as opposed to 60 Hz in US time zones due to differences in the anticipated noise from electrical sources within each continent. Thus, the S-ICD time zone was reprogrammed from EST to GMT, which reduced the notch filter from 60 to 50 Hz, resulting in S-ICD successfully eliminating EMI when the patient was in a supine position. The EMI interference was still intermittently present in the upright patient position. This case demonstrates the utility of high-resolution electrogram capture to identify the source and frequency of EMI in S-ICD and offers a potential avenue to troubleshoot dominant frequency oversensing by changing the device time zone.

Electromagnetic interference from left ventricular assist devices in patients with subcutaneous implantable cardioverter‐defibrillators

“…In addition, electromagnetic interference was not readily visible on standard device interrogation. High‐resolution capture can allow adequate visualization of electromagnetic interference 13 …”

“…A total of 10 cases of EMI in LVAD patients with S‐ICD devices, including the three cases described above, have been reported 10‐15 . A summary of the demographic characteristics of these patients is shown in Table 1.…”

“…However, EMI was not readily visible on standard device interrogation but was confirmed on the Marker Channel. These signals can be more readily visible using a high‐resolution capture setting 13 …”

“…This has been shown to interfere with TV‐ICD function, particularly with device interrogation 9 . Less is known regarding the impact of EMI from LVADs on S‐ICD function, as it is limited to sporadic cases, in which oversensing with inappropriate shocks (IASs) were delivered 10‐15 . Accordingly, in the present study, we present three cases of EMI observed in S‐ICD patients with LVAD, as well as a review of the literature.…”

Subcutaneous defibrillator lead management in a patient undergoing a sternotomy

“…report a case of S‐ICD undersensing following implantation of a HVAD (HeartWare Ventricular Assist Device, Medtronic, Minneapolis, MN, USA). This patient's S‐ICD was also turned off due to inability to troubleshoot the undersensing . Finally, there have been reports of inappropriate defibrillations in patients with S‐ICDs due to artifact attributed to air entrapment near the lead following implantation .…”