Electromagnetic Interference between Subcutaneous ICD and HeartMate II LVAD

Abstract

Introduction ICDs have been shown to have a significant benefit in reducing sudden cardiac death in patients with systolic heart failure. Additionally, cardiac devices as a bridge to transplant or destination therapy are often used in patients with end stage systolic heart failure. As a result most patients with LVADs also have an ICD. Subcutaneous ICD(S-ICD) was recently introduced into clinical trials to defibrillate ventricular arrhythmias, avoiding drawbacks of transvenous leads. It is therefore not surprising to find complexities arising such as this case of inappropriate S-ICD shock due to electromagnetic interference (EMI) between HeartMate II LVAD and S-ICD. Case Description A 31-year-old woman with a history of postpartum cardiomyopathy (American College of Cardiology stage D) was seen in the advanced heart Failure clinic with complaint of multiple S-ICD shocks over the last few months. The patient reported an implantation of a Boston Scientific S-ICD 7 months and a St. Jude HeartMate II LVAD as destination therapy 4 months prior to the presentation. S-ICD interrogation revealed multiple inappropriate shocks secondary to EMI between the two devices. Since the patient had no documented ventricular arrhythmias or history of ICD therapy prior to LVAD placement, it was decided to turn off the S-ICD and consider a transvenous ICD in the future if she should develop any significant arrhythmias. Conclusion EMI created by LVADs in the presence of an ICD has been previously described but to our knowledge this is the first case reporting EMI between HeartMate II and S-ICD. Multiple different methods have been described to resolve EMI between LVAD and transvenous ICD including “Pseudo” Faraday Cage and “Pan” methods. In cases of non-compatible devices, implantation of the transveous ICD in the contralateral side of LVAD has been also tried successfully, however it is unclear if repositioning the S-ICD pulse generator or the lead can change the vector adequately to avoid EMI. Additionally S-ICDs do not have the ability to engage in anti-tachycardia pacing to prevent shocks which are potentially lethal negative nootropic events in patients with severe LV dysfunction. Consequently, some patients may need transvenous ICD implantation to potentially resolve these issues. As cardiac devices continue to evolve, it is critical for advanced heart failure/ transplant cardiologists and electrophysiologists to understand potential interactions, and make appropriate pre-operative choices to eliminate this potential issue. Image 1: Close proximity of LVAD and S-ICD in our patient which potentially can increase the risk of EMI.