Subcutaneous implantable cardioverter defibrillators in patients with left ventricular assist devices: case report and comprehensive review

Left ventricular assist device in the presence of subcutaneous implantable cardioverter defibrillator: Data from a multicenter experience

BACKGROUND

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure (HF). Subcutaneous implantable cardioverter defibrillator (S-ICD) might be a viable alternative to conventional ICDs with a lower risk of short- and long-term of device-related complications and infections.The aim of this multicenter study was to evaluate the outcomes and management of S-ICD recipients who underwent LVAD implantation.

METHODS

The study population included patients with a preexisting S-ICD who underwent LVAD implantation for advanced HF despite optimal medical therapy.

RESULTS

The study population included 30 patients (25 male; median age 45 [38-52] years).The HeartMate III was the most common LVAD type. Median follow-up in the setting of concomitant use of S-ICDs and LVADs was 7 months (1-20).There were no reports of inability to interrogate S-ICD systems in this population. Electromagnetic interference (EMI) occurred in 21 (70%) patients. The primary sensing vector was the one most significantly involved in determining EMI. Twenty-seven patients (90%) remained eligible for S-ICD implantation with at least one optimal sensing vector. The remaining 3 patients (10%) were ineligible for S-ICD after attempts of reprogramming of sensing vectors. Six patients (20%) experienced inappropriate shocks (IS) due to EMI. Six patients (20%) experienced appropriate shocks. No S-ICD extraction because of need for antitachycardia pacing, ineffective therapy or infection was reported.

CONCLUSIONS

Concomitant use of LVAD and S-ICD is feasible in most patients. However, the potential risk of EMI oversensing, IS and undersensing in the post-operative period following LVAD implantation should be considered. Careful screening for EMI should be performed in all sensing vectors after LVAD implantation.

Subcutaneous implantable cardioverter-defibrillator noise following left ventricular assist device implantation

Background

The incidence and impact of noise in a subcutaneous implantable cardioverter defibrillator (S-ICD) after left ventricular assist device (LVAD) implantation is not well established.

Methods

We performed a retrospective study of patients implanted with LVAD and with a pre-existing S-ICD between January 2005 and December 2020 at the three Mayo Clinic centers (Minnesota, Arizona, and Florida).

Results

Of the 908 LVAD patients, a pre-existing S-ICD was present in 9 patients (mean age 49.1 ± 13.7 years, 66.7% males), 100% with Boston Scientific third-generation EMBLEM MRI S-ICD, 11% with HeartMate II (HM II), 44% with HeartMate 3 (HM 3), and 44% with HeartWare (HW) LVAD. The incidence of noise from LVAD-related electromagnetic interference (EMI) was 33% and was only seen with HM 3 LVAD. Multiple measures attempted to resolve noise, including using alternative S-ICD sensing vector, adjusting S-ICD time zone, and increasing LVAD pump speed, were unsuccessful, necessitating S-ICD device therapies to be turned off permanently.

Conclusions

The incidence of LVAD-related S-ICD noise is high in patients with concomitant LVAD and S-ICD with significant impact on device function. As conservative management failed to resolve the EMI, the S-ICDs had to be programmed off to avoid inappropriate shocks. This study highlights the importance of awareness of LVAD-SICD device interference and the need to improve S-ICD detection algorithms to eliminate noise.

Device-device interaction between cardiac implantable electronic devices and continuous-flow left ventricular assist devices

The current design of an innovative left ventricular assist device (LVAD) makes use of magnetic levitation technology, which enables the rotors of the device to be completely suspended by magnetic force, reducing friction and blood or plasma damage. However, this electromagnetic field can result in electromagnetic interference (EMI), which can interfere with proper functioning of another cardiac implantable electronic device (CIED) in its direct proximity. Approximately 80% of patients with an LVAD have a CIED, most frequently an implantable cardioverter-defibrillator (ICD). Several device-device interactions have been reported, including EMI-induced inappropriate shocks, inability to establish telemetry connection, EMI-induced premature battery depletion, undersensing by the device, and other CIED malfunctions. Unfortunately, additional procedures, including generator exchange, lead adjustment, and system extraction, are frequently required because of these interactions. In some circumstances, the additional procedure might be preventable or avoidable with appropriate solutions. In this article, we describe how EMI from the LVAD impacts the functionality of the CIED and provide possible management options, including manufacturer-specific information, for the current CIEDs (eg, transvenous and leadless pacemakers, transvenous and subcutaneous ICDs, and transvenous cardiac resynchronization therapy pacemakers and ICDs).

Electromagnetic interference between implantable cardiac devices and continuous-flow left ventricular assist devices: a review

Many patients with continuous-flow left ventricular assist devices (CF-LVAD) have other, co-existing implantable cardiac devices. While such devices often function appropriately, there is potential for electromagnetic interference (EMI). A literature review was performed to identify cases of EMI between CF-LVAD and other implanted cardiac devices to better understand their etiology, outcomes, and the strategies used to overcome such interference. The cases identified included interference between CF-LVAD and pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy. The EMI reported in the current literature can be broken down into two general categories: interference leading to difficulty establishing telemetry and interference leading to impaired electrical signal sensing. Such interference led to inappropriate shock delivery in some cases. The type of interference, and thus treatments, differed and were device dependent. The strategies employed to reduce interference included metal shielding, physical manipulation to increase the distance between devices, and even exchange of the implanted device with another brand of the same class. To avoid such EMI in the future, physicians must be aware of the reported interference between certain devices, and manufacturers must work more closely to increase the compatibility of implanted cardiac devices.

[ICD and left ventricular assist device interference: Case report]

Left ventricular assist devices are used for severe chronic heart failure management. Many of these patients have an implantable cardioverter defibrillator (ICD). However electromagnetic interferences are possible between the 2 devices. We report here a case of an interference in a 77 years-old patient. This was associated with an impossibility to communicate with the ICD. We discuss how to manage this situation.

Reducing ECG Artifact From Left Ventricular Assist Device Electromagnetic Interference

Background Left ventricular assist devices (LVADs) generate electromagnetic interference that causes high-frequency noise artifacts on 12-lead ECGs. We describe the causes of this interference and potential solutions to aid ECG interpretation in patients with LVAD. Methods and Results Waveform data from ECGs performed before and after LVAD implantation were passed through a fast Fourier transform to identify LVAD-related changes in the spectral profile. ECGs recorded in 9 patients with HeartMate II, HeartMate 3, and HeartWare LVADs were analyzed to identify the LVAD model-specific spectral patterns. Waveform data were then passed through digital low-pass and bandstop filters and redisplayed to evaluate the effect of filtering on LVAD-related electromagnetic interference. The spectral profile of patients with HeartMate II and HeartMate 3 LVADs demonstrated a prominent signal at the device-specific frequency of impeller rotation. In patients with the HeartMate 3 LVAD, 2 additional peaks were observed at the frequencies equivalent to the LVAD's artificial pulsatility rotational speeds. Patients with HeartWare devices demonstrated a prominent signal peak at a frequency equal to double their LVAD's set rotational speed. Applying a low-pass filter to a value below the observed frequency peak from the LVAD significantly improved the waveform tracing and quality of the ECG. Applying a speed-specific bandstop filter to remove the observed LVAD frequency peak also improved the clarity of the ECG without compromising physiological high-frequency signal components. Conclusions LVADs create impeller rotational speed-specific electromagnetic interference that can be ameliorated by application of low-pass or bandstop filters to improve ECG clarity.

Eligibility for subcutaneous implantable cardioverter-defibrillator in patients with left ventricular assist device

Purpose

The subcutaneous implantable cardioverter-defibrillator (S-ICD) could be a promising alternative to the conventional transvenous ICD in patients with LVAD due to its reduced risk of infection. However, surface ECG is altered following LVAD implantation and, since S-ICD detection is based on surface ECG, S-ICD could be potentially affected. The aim of the present study was to analyze S-ICD eligibility in patients with LVAD.

Methods

Seventy-five patients implanted with an LVAD were included in this prospective single-center study. The ECG-based screening test and the automated screening test were performed in all patients.

Results

Fifty-five (73.3%) patients had either a positive ECG-based or automated screening test. Out of these, 28 (37.3%) patients were found eligible for S-ICD implantation with both screening tests performed. ECG-based screening test was positive in 50 (66.6%) patients; automated screening test was positive in 33 (44.0%) patients. Three ECG-based screening tests could not be evaluated due to artifacts. With the automated screening test, in 9 (12.0%) patients, the test yielded no result.

Conclusions

Patients implanted with an LVAD showed lower S-ICD eligibility rates compared with patients without LVAD. With an S-ICD eligibility rate of maximal 73.3%, S-ICD therapy may be a feasible option in these patients. Nevertheless, S-ICD implantation should be carefully weighed against potential device-device interference. Prospective studies regarding S-ICD eligibility before and after LVAD implantation are required to further elucidate the role of S-ICD therapy in this population.