Subcutaneous Implantable Cardioverter-Defibrillator Shocks After Left Ventricular Assist Device Implantation.

Abstract

HomeCirculation: Arrhythmia and ElectrophysiologyVol. 9, No. 11Subcutaneous Implantable Cardioverter-Defibrillator Shocks After Left Ventricular Assist Device Implantation Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBSubcutaneous Implantable Cardioverter-Defibrillator Shocks After Left Ventricular Assist Device Implantation Tobias J. Pfeffer, MD, Thorben König, MD, David Duncker, MD, Roman Michalski, MD, Stephan Hohmann, MD, Hanno Oswald, MD, Jan D. Schmitto, MD and Christian Veltmann, MD Tobias J. PfefferTobias J. Pfeffer From the Department of Cardiology and Angiology (T.J.P., T.K., D.D., R.M., S.H., H.O., C.V.) and Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (J.D.S.), Hannover Medical School, Germany. Search for more papers by this author , Thorben KönigThorben König From the Department of Cardiology and Angiology (T.J.P., T.K., D.D., R.M., S.H., H.O., C.V.) and Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (J.D.S.), Hannover Medical School, Germany. Search for more papers by this author , David DunckerDavid Duncker From the Department of Cardiology and Angiology (T.J.P., T.K., D.D., R.M., S.H., H.O., C.V.) and Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (J.D.S.), Hannover Medical School, Germany. Search for more papers by this author , Roman MichalskiRoman Michalski From the Department of Cardiology and Angiology (T.J.P., T.K., D.D., R.M., S.H., H.O., C.V.) and Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (J.D.S.), Hannover Medical School, Germany. Search for more papers by this author , Stephan HohmannStephan Hohmann From the Department of Cardiology and Angiology (T.J.P., T.K., D.D., R.M., S.H., H.O., C.V.) and Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (J.D.S.), Hannover Medical School, Germany. Search for more papers by this author , Hanno OswaldHanno Oswald From the Department of Cardiology and Angiology (T.J.P., T.K., D.D., R.M., S.H., H.O., C.V.) and Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (J.D.S.), Hannover Medical School, Germany. Search for more papers by this author , Jan D. SchmittoJan D. Schmitto From the Department of Cardiology and Angiology (T.J.P., T.K., D.D., R.M., S.H., H.O., C.V.) and Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (J.D.S.), Hannover Medical School, Germany. Search for more papers by this author and Christian VeltmannChristian Veltmann From the Department of Cardiology and Angiology (T.J.P., T.K., D.D., R.M., S.H., H.O., C.V.) and Department of Cardiac, Thoracic, Transplantation and Vascular Surgery (J.D.S.), Hannover Medical School, Germany. Search for more papers by this author Originally published28 Oct 2016https://doi.org/10.1161/CIRCEP.116.004633Circulation: Arrhythmia and Electrophysiology. 2016;9:e004633Case ReportA 42-year-old man experiencing nonischemic cardiomyopathy with severely reduced left ventricular function and advanced heart failure met the criteria for primary prophylactic implantation of an implantable cardioverter-defibrillator (ICD). A subcutaneous ICD (S-ICD; EMBLEM; Boston Scientific, Marlborough, MA) was implanted at a secondary center in November 2015 with the lead (3401; Boston Scientific) tunnelled in left parasternal position. Before implantation, surface ECG screening was performed following the manufacturer’s instructions.A few weeks later, the patient was transferred to Hannover Medical School because of heart failure deterioration (New York Heart Association class IV). After careful evaluation, a continuous-flow left ventricular assist device (LVAD; HeartMate 3; Thoratec, Pleasanton, CA) was implanted using conventional sternotomy.1 Approximately 1 hour after LVAD implantation, the patient received 31 S-ICD shocks. The device was immediately deactivated. Interrogation of the S-ICD revealed normal sinus rhythm during the shocks. However, R waves were diminished and superimposed by electric noise caused by the LVAD. Oversensing of electromagnetic interference led to all S-ICD shocks (Figure 1). Manually, all 3 sensing vectors, primary, secondary, and alternate at all available gain settings, were tested for adequate R wave sensing. In not a single configuration, the S-ICD was able to differentiate between R wave and T wave. Even flutter waves (F waves) were discriminated as R waves by the S-ICD (Figure 2). Thus, after LVAD implantation, S-ICD therapy was not feasible any more.Download figureDownload PowerPointFigure 1. Subcutaneous implantable cardioverter-defibrillator (ICD) ECG with primary sensing vector showing inappropriate ICD shock because of oversensing of electric noise caused by the left ventricular assist device.Download figureDownload PowerPointFigure 2. Subcutaneous implantable cardioverter-defibrillator (ICD) ECG with alternate sensing vector showing oversensing of flutter waves and T waves. In this vector, no electromagnetic interference could be observed.Surface ECG screening was repeated after LVAD implantation. Both left and right parasternal electrode placement showed low R wave amplitudes and confirmed the inability of the S-ICD to differentiate between F, R, and T wave (Figure 3).Download figureDownload PowerPointFigure 3. Screening ECG after left ventricular assist device implantation. The ECG showed atrial flutter with low voltage of the R waves. Lead I indicates the alternate sensing vector, lead II the secondary sensing vector, and lead III the primary sensing vector. (paper speed 25 mm/s).After completion of rehabilitation period, the S-ICD was explanted and a conventional transvenous single-chamber ICD was implanted. During a follow-up of 6 months, the ICD showed a regular device function. Up to now, no oversensing or inappropriate therapy occurred.DiscussionThis case report illustrates inappropriate S-ICD shocks because of changes in R wave morphology and amplitude after LVAD implantation. Changes in ECG morphology after LVAD implantation have been described previously.2 However, these consequences need special consideration when surface ECG–based systems like the S-ICD are used.There are only few case reports dealing with the combination of S-ICD and LVAD therapy. One case describes successful combination of an LVAD (HeartMate II; Thoratec) and an S-ICD (SQ-RX pulse generator model 1010; Boston Scientific) without any electromagnetic interference.3Saeed et al4 reported a case in which electromagnetic interference between the S-ICD and the LVAD (HVAD; HeartWare International, Inc, Framingham, MA) was observed. Two out of 3 sensing vectors showed electromagnetic interference after LVAD implantation. The electromagnetic noise was correctly classified by the S-ICD and did not lead to inappropriate shocks.To our knowledge, this report describes the first case with inappropriate S-ICD shocks after LVAD implantation. The S-ICD shocks were caused by electromagnetic interference, changes in R wave morphology, and a decreased R wave amplitude after LVAD implantation.Low voltage of R wave is commonly observed after LVAD implantation.2 Because the device automatically adjusts its sensing threshold to the amplitude of the last sensed events, postoperative low voltage increases the risk of ventricular oversensing.ConclusionsOn the basis of our experience, we recommend deactivation of the antitachycardia therapy of the S-ICD before LVAD implantation. After recovery from surgery and before reactivation of the device, all sensing vectors should be evaluated with respect to adequate sensing and differentiation of R wave and T wave.Because of sparse and inconsistent data about the combination of S-ICDs and LVADs, we recommend to avoid this combination until data have become more conclusive. If a combination of S-ICD and LVAD cannot be avoided, postoperative follow-up should be performed with great caution and under close surveillance, as proposed above.DisclosuresD. Duncker has received a fellowship grant and travel support from Boston Scientific. C. Veltmann has received honoraria for speeches and presentations from Boston Scientific. The other authors report no conflicts.FootnotesCorrespondence to Christian Veltmann, MD, Medizinische Hochschule Hannover, Klinik für Kardiologie und Angiologie, Carl-Neuberg-Str.1, 30625 Hannover, Germany. E-mail [email protected]