Case Study

A Tale of 2 Devices: ICD Lead Malfunction Following Implantation of a Left Ventricular Assist Device

Christopher Purtell, MD, Cardiovascular Medicine Fellow, and Miguel Leal, MD, Director of the
Electrophysiology & Arrhythmia Service

University of Wisconsin, Madison, Wisconsin

Christopher Purtell, MD, Cardiovascular Medicine Fellow, and Miguel Leal, MD, Director of the
Electrophysiology & Arrhythmia Service

University of Wisconsin, Madison, Wisconsin

Given the growing number of patients with advanced heart failure who require mechanical circulatory support, notably the placement of left ventricular assist devices (LVADs) either as destination therapy or as bridge-to-transplant, it is important to understand potential complications that may arise in patients with pre-existing endovascular hardware.1 Two of the newer-generation devices are the HeartMate 3 LVAD (Abbott) and the HeartWare HVAD System (Medtronic). The HeartMate 3 is a fully magnetically levitated centrifugal continuous-flow pump that was FDA approved in 2017 based on data published in the MOMENTUM-3 Trial.2 In comparison, the HeartWare is a centrifugal-flow device that uses a hydromagnetically suspended rotor that may be inserted into the pericardial space.3

Several studies have demonstrated adverse events involving previously implanted defibrillator (ICD) leads following implantation of these mechanical circulatory supporting devices.4–8 A single-center study published in 2014 assessed ICD lead parameters, performance, and adverse events following continuous-flow LVAD implantation from 2008-2010.5 They found a significant number of ICD-related adverse events following LVAD implantation, requiring both invasive and non-invasive ICD system modification. There was also a significant reduction in ICD sensing measurements.5 A similar study published in 2010 assessed patients undergoing LVAD implantation between 2000 and 2009, and found that lead revision and extraction were frequently required following those surgeries.9

Given the significant burden of ventricular tachyarrhythmias after LVAD implantation, it is important to routinely evaluate the function of ICD leads shortly after LVAD implantation.4 Since the HeartMate 3 and HeartWare are newer devices with different physical profiles and surgical implant techniques, it is important to re-evaluate the complications that may be associated with these devices. The following 2 cases demonstrate different approaches to dealing with lead malfunction after LVAD implantation.

Case Presentations

Case #1:

The first patient is a 38-year-old female with a history of paroxysmal atrial fibrillation and atrial flutter, status-post pulmonary vein isolation and cavotricuspid isthmus (CTI) ablation, peripartum cardiomyopathy, chronic systolic heart failure associated with severely reduced left ventricular ejection fraction (25%), and ventricular fibrillation status-post a dual-chamber ICD implant; she was initially transferred from a referring institution in cardiogenic shock. She had recently undergone third-trimester termination of her pregnancy, with concerns that this may have exacerbated her underlying cardiomyopathy.

Upon transfer to our center, she underwent evaluation by the advanced heart failure team and was deemed a candidate for implantation of an LVAD. She received a HeartMate 3 device along with a tricuspid valve (ring) repair. A pre-surgical device interrogation of her dual-chamber ICD demonstrated stable device settings and minimal atrial and ventricular pacing needs, as well as good battery longevity, and her underlying rhythm was sinus as per EGM analysis. A post-operative device check revealed failure to capture by the right ventricular (RV) ICD lead (Table 1), in addition to other electrical abnormalities.

Following this procedure, she had multiple runs of non-sustained ventricular tachycardia, but remained predominantly in sinus rhythm. A post-operative chest x-ray demonstrated the occurrence of a clear deformity of the distal segment of the RV ICD lead, with an acute bend involving the distal coil (Figure 1). Based on these findings, and after discussion with the cardiac surgeon, it was determined that this RV ICD lead was entrapped by the sewing ring of the LVAD cuff. Upon review of this case, it was decided that lead extraction could not be performed without potentially damaging the LVAD itself. Therefore, the RV ICD lead was capped and a new ICD lead was implanted.

Case #2:

The second patient is a 41-year-old female with a history of chemotherapy-induced non-ischemic cardiomyopathy, chronic systolic heart failure associated with a severely reduced left ventricular ejection fraction (20%), non-Hodgkin’s lymphoma, atrial fibrillation, atrial flutter (status-post catheter ablation of the CTI), and previous implant of a dual-chamber ICD 10 months prior for primary prevention of sudden cardiac death. She initially presented with acute exacerbation of her underlying chronic systolic heart failure, manifested with a volume-overloaded state. She required the placement of an intra-aortic balloon pump for additional hemodynamic support, in anticipation of a HeartWare LVAD implantation.

Pre-operative device interrogation of her dual-chamber ICD demonstrated stable device settings compared to 2 months prior. A bedside device evaluation performed on the day after implantation of the HeartWare device indicated stable atrial lead measurements; however, the RV ICD lead showed substantial decreases in both the pacing impedance and sensitivity measurements, along with an elevated RV capture threshold. The device underwent repeat interrogation 48 hours later without any significant changes (Table 2). Comparison of chest x-rays before and after the surgery demonstrated that the LVAD cuff was in close proximity to the RV ICD lead tip (Figure 2). Based on these findings, the decision was made to proceed with ICD lead extraction and replacement.

The patient was brought to the EP hybrid lab and received general anesthesia. The existing single-coil, active-fixation RV ICD lead was extracted. A clearing stylet was placed in the lead lumen for added mechanical stability and the distal screw was partially retracted. The lead was removed in its entirety via gentle manual traction — no laser-assisted dissection was required. A new single-coil RV ICD lead was then placed in the RV septum, purposefully away from the apical segment. There were no complications.

Discussion

These 2 cases, which interestingly occurred less than one month apart, illustrate a potential complication that may arise following implantation of an LVAD, including newer-generation devices such as the HeartMate 3 and HeartWare HVAD. Due to the surgical techniques that are applied to secure these devices in place, the LVAD apical cannula sewing ring may interfere with the right ventricular ICD lead or ensnare it (Figure 1), particularly if the ICD lead is placed in an apical or distal septal position. In the cases presented here, both affected ICD leads had been originally implanted in the distal right ventricular septum, in very close proximity to the RV apex.

Despite the surgical team’s extensive experience with implantation of mechanical circulatory support (MCS) devices over that past 15 years, our observations reveal that there is a significant surgical learning curve with implantation of these newer generation devices. These devices are significantly smaller in size than prior generations and require a different surgical technique for adequate fixation of the inflow cannula into the left ventricular apex. These 2 cases led to modifications of the surgical implant technique, with special attention paid to the thickness of the sewing ring at the level of the distal interventricular septum and right ventricular apex, which is often the site where the ventricular pacemaker or defibrillator lead is implanted.

The intrinsic characteristics of the newer-generation LVADs may have an association with the findings described in our case series, to the extent that the surgical technique should ideally realize the potential consequences of such LVAD implants to existing intracardiac hardware. These cases also highlight the importance of careful monitoring of the performance of pacemakers and defibrillators in patients post-LVAD implant, in order to allow for early recognition of any potential abnormalities that may require invasive (ie, lead revision) or non-invasive (eg, electronic reprogramming) intervention.

Both cases revealed pacing issues in the post-operative state, manifested by either a significant rise in the right ventricular capture threshold or complete failure to capture despite maximum pacing outputs, as well as poor ventricular sensing parameters. The atrial leads were unaffected in either case and did not require any specific invasive or non-invasive revisions. The decision whether to proceed with laser-assisted lead extraction or capping and abandonment of the previously implanted lead needs to be individualized, with patient-specific risks, benefits, and preferences carefully assessed and included in the decision-making process.

In the first of the 2 reported cases, it was clear from the positioning of the sewing ring cuff that lead extraction would very likely damage or disrupt the LVAD ventricular cannula implant site. Therefore, a prudent decision was made to abandon that lead and proceed with implantation of a new lead. In the second case, pre-procedural imaging was helpful in predicting that lead extraction may be performed in the vicinity of the LVAD cuff in the appropriate clinical scenarios.

Summary

In comparison with prior LVAD generations, the miniaturized profile of these particular devices may actually be associated with a potentially higher risk of ICD lead malfunction if surgical technique does not account for the co-location of the right ventricular pacemaker or defibrillator leads. These 2 cases illustrate that pre-operative and post-operative device interrogations need to be routinely performed to quickly identify any abnormal lead parameters, with the goals of ensuring patient safety and adequate planning for invasive intervention, if necessary. 

Disclosures: The authors have no conflicts of interest to report regarding the content herein. Outside the submitted work, Dr. Leal reports a fellowship training grant from Medtronic.

References
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