Subcutaneous implantable cardioverter-defibrillator troubleshooting in patients with a left ventricular assist device: A case series and systematic review

Decision-making regarding subcutaneous implantable cardioverter defibrillator as primary prevention in patients with low ejection fraction

BACKGROUND

Conventional transvenous implantable cardioverter-defibrillator (TV-ICD) is the standard device used for primary prevention of sudden cardiac death (SCD) in patients with reduced left ventricular ejection fraction (LVEF). Nonetheless its use is associated with lead-related complications including infection and malfunction. A subcutaneous implantable cardioverter-defibrillator (S-ICD) offers an alternative option without the need for a transvenous lead but has limitations. The decision to implant a TV-ICD or S-ICD in patients with impaired LVEF for primary prevention of SCD is controversial. Several randomised controlled trials and large observational studies have confirmed similar safety and efficacy of S-ICDs and TV-ICDs in such population.

METHODS

A literature review was conducted to compare the outcomes of subcutaneous (S-ICD) versus transvenous (TV-ICD) implantable cardioverter-defibrillators. Databases including PubMed, MEDLINE, and Cochrane were searched for relevant peer-reviewed articles. Studies were selected based on relevance and quality. Key outcomes like complication rates, efficacy, and patient survival were summarized in a comparative table.

RESULTS

Different factors that influence the choice between an TV-ICD and S-ICD for primary prevention of SCD in patients with LVEF are highlighted to guide selection of the appropriate device in different patient populations. Moreover, future perspective on the combination of SICD with leadless pacemaker, and the latest development of the extravascular implantable cardioverter defibrillator are also discussed.

CONCLUSIONS

S-ICD offers a safe and efficacious option to primary prevention in reduced ejection fraction. Future development including incorporation of leadless pacemaker will add to the arsenal of choice to protect patients from sudden cardiac death.

Appropriate and inappropriate ICD shocks in patients with LVADs: Prevalence, associated factors, and etiologies

BACKGROUND

Implantable cardioverter-defibrillator (ICD) shocks are a common complication after left ventricular assist device (LVAD) implantation; however, data on their frequency and causes are limited.

OBJECTIVE

The purpose of this study was to define the incidence, programming, patient characteristics, and factors associated with appropriate and inappropriate ICD shocks in persons with LVADs.

METHODS

We performed a retrospective review at Duke University Hospital of all LVAD recipients implanted between January 1, 2013, to June 30, 2019, with a preexisting ICD. ICD shocks were adjudicated by the treating physician and a second reviewer for the purpose of this study.

RESULTS

Among 421 patients with an ICD in situ undergoing LVAD implant, 147 (33.9%) had at least 1 shock after LVAD implantation. Among 134 patients with complete device history, a total of 330 shock episodes occurred: 255 (77.3%) appropriate and 75 (22.7%) inappropriate. Etiologies for inappropriate shocks included supraventricular tachycardia (n = 66 [20.0%]), physiological oversensing (n = 1 [0.3%]), and nonphysiological oversensing (n = 8 [2.4%]) including LVAD electromagnetic interference (n = 1 [0.3%]). ICD programming with shorter detection delay (P <.001) and absence of antitachycardia pacing programming (P = .001) in high-rate zones was seen more commonly in inappropriate shock than appropriate shock.

CONCLUSIONS

The rate of inappropriate shocks in LVAD recipients is very high and most often is due to supraventricular arrhythmias. LVAD electromagnetic interference is a rare cause of ICD shock. Implementation of current consensus American Heart Association recommendations for LVAD programming with long detection delays and high rate cutoffs may help prevent inappropriate ICD shocks.

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).

Simultaneous Leadless Pacemaker and Subcutaneous ICD Implantation With Intraoperative Screening: Workflow in Two Patients

A communicating subcutaneous implantable cardioverter-defibrillator (ICD) and leadless pacemaker system is being developed for patients who require both pacing and ICD therapy. It is important to ensure that the paced morphology from the leadless pacemaker will be sensed appropriately by the subcutaneous ICD. We present 2 cases illustrating our approach and workflow. (Level of Difficulty: Intermediate.).

Subcutaneous implantable cardioverter defibrillator after transvenous lead extraction: safety, efficacy and outcome

BACKGROUND

Subcutaneous implantable cardioverter defibrillator (S-ICD) is a suitable alternative for transvenous ICD (TV-ICD) patients who have undergone transvenous lead extraction (TLE). Limited data are available on the outcome of S-ICD patients implanted after TLE. We assessed the safety, efficacy, and outcome of S-ICD implantation after TLE of TV-ICD.

METHODS

The study population consisted of 36 consecutive patients with a median age of 52 (44-66) years who underwent S-ICD implantation after TLE of TV-ICD.

RESULTS

Indications for TLE were infection (63.9%) and lead malfunction (36.1%). During a median follow-up of 31 months, 3 patients (8.3%) experienced appropriate therapy and 7 patients (19.4%) experienced complications including inappropriate therapy (n = 4; 11.1%), isolated pocket erosion (n = 2; 5.5%), and ineffective therapy (n = 1; 2.8%). No lead/hardware dysfunction was reported. Premature device explantation occurred in 4 patients (11%). Eight patients (22.2%) died during follow-up, six of them (75%) because of refractory heart failure (HF). There were no S-ICD-related deaths. Predictors of mortality included NYHA class ≥ 2 (HR 5.05; 95% CI 1.00-26.38; p = 0.04), hypertension (HR 22.72; 95% CI 1.05-26.31; p = 0.02), diabetes (HR 10.64; 95% CI 2.05-55.60; p = 0.001) and ischemic heart disease (HR 5.92; 95% CI 1.17-30.30; p = 0.01).

CONCLUSION

Our study provides evidences on the use of S-ICD as an alternative after TV-ICD explantation for both infection and lead failure. Mortality of S-ICD patients who underwent TV-ICD explantation does not appear to be correlated with the presence of a prior infection, S-ICD therapy (appropriate or inappropriate), or S-ICD complications but rather to worsening of HF or other comorbidities.

Subcutaneous and Transvenous ICDs: an Update on Contemporary Questions and Controversies

PURPOSE OF REVIEW

While the subcutaneous (S-) implantable cardioverter-defibrillator (ICDs) is an alternative to the transvenous (TV-) ICD in many patients, optimal use remains unclear. In this review, we summarize recent clinically relevant data on sensing algorithms, inappropriate shocks, defibrillation testing, and battery and electrode failures.

RECENT FINDINGS

Changes in sensing algorithms and S-ICD programming have significantly decreased inappropriate shock rates. Avoiding fat below the S-ICD coil and can is key for reducing the defibrillation threshold. While S-ICD battery and electrode failures have resulted in recalls, system components remain commercially available since failure rates are low and no other similar devices are available. The S-ICD is a good alternative to the TV-ICD for many patients, and particularly in light of recently developed device algorithms and improvements in implant technique. Future research will need to better understand: the impact of S-ICD electrode and battery failures and the potential for integrating leadless pacing into a modular S-ICD platform.

Outcomes of Digital Biomarker-Based Interventions: Protocol for a Systematic Review of Systematic Reviews

BACKGROUND

Digital biomarkers are defined as objective, quantifiable, physiological, and behavioral data that are collected and measured using digital devices such as portables, wearables, implantables, or digestibles. For their widespread adoption in publicly financed health care systems, it is important to understand how their benefits translate into improved patient outcomes, which is essential for demonstrating their value.

OBJECTIVE

The paper presents the protocol for a systematic review that aims to assess the quality and strength of the evidence reported in systematic reviews regarding the impact of digital biomarkers on clinical outcomes compared to interventions without digital biomarkers.

METHODS

A comprehensive search for reviews from 2019 to 2020 will be conducted in PubMed and the Cochrane Library using keywords related to digital biomarkers and a filter for systematic reviews. Original full-text English publications of systematic reviews comparing clinical outcomes of interventions with and without digital biomarkers via meta-analysis will be included. The AMSTAR-2 tool will be used to assess the methodological quality of these reviews. To assess the quality of evidence, we will evaluate the systematic reviews using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. To detect the possible presence of reporting bias, we will determine whether a protocol was published prior to the start of the studies. A qualitative summary of the results by digital biomarker technology and outcomes will be provided.

RESULTS

This protocol was submitted before data collection. Search, screening, and data extraction will commence in December 2021 in accordance with the published protocol.

CONCLUSIONS

Our study will provide a comprehensive summary of the highest level of evidence available on digital biomarker interventions, providing practical guidance for health care providers. Our results will help identify clinical areas in which the use of digital biomarkers has led to favorable clinical outcomes. In addition, our findings will highlight areas of evidence gaps where the clinical benefits of digital biomarkers have not yet been demonstrated.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/28204.

Electromagnetic interference from left ventricular assist device in patients with transvenous implantable cardioverter-defibrillator

BACKGROUND

Many advanced heart failure patients have both a left ventricular assist device (LVAD) and an implantable cardioverter-defibrillator (ICD). This study examines incidence, clinical impact, and management of LVAD-related EMI.

METHODS

We performed a three-center retrospective analysis of transvenous ICD implanted patients with LVAD implanted between January 1, 2005 and December 31, 2020. The primary outcome was EMI after LVAD implantation, categorized as LVAD-related noise or telemetry interference.

RESULTS

The rate of LVAD-related EMI among the 737 patients (mean age 58.6 ± 12.8 years) studied was 5.0%. Telemetry interference (1.5%) compromised ICD interrogation in all patients. This was resolved successfully with use of a metal shield, encased wand, radiofrequency tower, different ICD programmer or by increasing distance between ICD programmer and LVAD (n = 6). ICD replacement was required to reestablish successful communication in three patients. LVAD-related noise (3.5%) led to oversensing (n = 4), inappropriate mode switches (n = 4), noise reversion (n = 3), inhibition of pacing (n = 2), inappropriate detection as atrial fibrillation (AF) (n = 2) and inappropriate detection as ventricular tachycardia (VT) and/or ventricular fibrillation (VF) (n = 2). This noise interference persisted (n = 3), resolved spontaneously (n = 16), resolved with programming change (n = 6) or required lead revision (n = 1).

CONCLUSIONS

EMI from LVAD impacts ICD function, although, the incidence rate is low. Physicians implanting both, LVAD in patients with ICD (more common) or ICD in patients with LVAD, should be aware of possible interferences. Telemetry failure not resolved by metal shielding was overcome by ICD generator replacement to a different manufacturer. In most cases, LVAD-related noise resolves spontaneously.

A novel screening tool to unmask potential interference between S-ICD and left ventricular assist device

INTRODUCTION

In patients with a left ventricular assist device (LVAD), the subcutaneous implantable cardioverter-defibrillator (S-ICD) can be an alternative to transvenous ICD systems due to reduced risk of systemic infection, which could lead to extraction of the ICD as well as the LVAD. S-ICD eligibility is lower in patients with LVAD than in patients with end-stage heart failure without LVAD. Several reports have shown inappropriate S-ICD therapy in the coexistence of LVAD and S-ICD. The aim of the present study was to evaluate S-ICD eligibility in patients with LVAD using the established electrocardiogram (ECG)-based screening test as well as a novel device-based screening test to identify potentially inappropriate S-ICD sensing in this specific patient cohort.

METHODS AND RESULTS

The present study included 115 patients implanted with an LVAD. The standard ECG-based screening test and a novel device-based screening test were performed in all patients. Eighty patients (70%) were eligible for S-ICD therapy with the standard ECG-based screening test. Performance of the novel device-based screening test identified device-device interference in 14 of these 80 patients (12%).

CONCLUSION

Using a novel extended device-based S-ICD screening method, a small number of patients with LVAD deemed eligible for S-ICD with the standard ECG-based screening test exhibit device-device interference. Careful S-ICD screening should be performed in patients with LVAD, who are candidates for S-ICD therapy, to prevent inappropriate sensing or ICD therapy.