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      Direct visualization of an atrial transseptal left ventricular endocardial lead implantation within an isolated heart

      case-report

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          Abstract

          KEY TEACHING POINTS • Implantation of an LV endocardial lead is feasible using a superior atrial transseptal approach. • A catheter-based delivery system with RF wire can be used to locate and puncture the atrial septum, and subsequently guide/implant an active fixation lead in the LV with minimal steps. • An LV endocardial lead can be placed without impingement of the mitral valve. Introduction Left ventricular (LV) endocardial pacing is a relatively new therapy that may offer several advantages over coronary venous lead placement for biventricular resynchronization therapy, including access to more regions of the LV, faster impulse propagation, avoidance of phrenic nerve stimulation, and more physiologic LV activation. 1 We report a case of transseptal implantation of a pacing lead in the LV chamber from a superior approach, which was observed using direct visualization, for better understanding of the implantation procedure and device–tissue interactions during the procedural steps. Case report Endoscopic cameras (IplexFX, Olympus Corporation, Tokyo, Japan) were placed within the right atrium, left atrium (LA), and LV of a human donor heart (LifeSource, St. Paul, MN) that was deemed not viable for transplantation. The heart was reanimated and perfused with a clear Krebs–Henseleit buffer according to previously described methodologies.2, 3 The intrinsic sinus rhythm of the beating heart was 70 bpm. An external view of the experimental setup is shown in Figure 1 and Online Supplementary Video 1. Initially, the right atrial septum was located using a deflectable catheter, and the fossa ovalis was tented using a dilator and a subselection catheter as viewed from the right atrium (Figure 2A) and LA (Figure 2B) (the delivery system, leads, and implant technique are not approved for investigational or commercial use in the United States). The fossa ovalis then was punctured using a radiofrequency (RF) wire (Figure 2C) and a generator (25 W at 2 seconds), and the RF wire (Baylis Medical Inc, Montreal, Quebec, Canada) was advanced into the LA (Figure 2D). The dilator was subsequently placed across the fossa ovalis within the LA using the RF wire as a guide (Figure 2E). Next, a subselection catheter was placed over the dilator, across the septum and into the LA (Figure 2F). After the dilator was withdrawn, the subselection catheter was directed toward the mitral valve, and the RF wire was advanced across the mitral valve without impinging on the chordae tendineae or leaflets (Figure 2G). Thereafter, the subselection catheter was guided over the RF wire and across the mitral valve (Figure 2H). The RF wire was removed, which allowed the subselection catheter to move freely within the LV. Note that in a clinical setting, a pressurized, continuous heparinized saline flush would then be attached to subselection catheter after removal of the RF wire. The subselection catheter was positioned on the lateral free wall of the LV, and an active fixation lead (3830 SelectSecure, Medtronic Inc, Mounds View, MN) was inserted into the catheter and fixated (Figure 2I). After fixation, the subselection catheter was withdrawn to ensure that the lead was fully fixated in the myocardium. The procedure can be viewed in Online Supplementary Video 1. Discussion LV endocardial lead placement enables physiologic pacing and freedom to select an optimal LV pacing site in order to improve cardiac resynchronization therapy (CRT) outcome.4, 5, 6 Garrigue et al 7 studied 15 patients with epicardial lead implants via the coronary sinus and compared them with 8 patients with endocardial leads placed by conventional transseptal puncture secondary to unsuitable coronary sinus anatomy. They reported a significant improvement in echocardiographic and Doppler variables in the patients who had undergone endocardial pacing. In addition, Bracke et al 8 reported that endocardial LV pacing improved clinical efficacy in a nonresponder who previously had been implanted with a traditional CRT system. As such, implementation of endocardial LV pacing ultimately will depend on safe, effective, durable instrumentation and reliable, reproducible intraprocedural methods to identify the optimal LV pacing site. Another key to the future success of this pacing technique will be the ability to demonstrate significant benefit of LV endocardial pacing over the risk associated with thromboembolism in advanced heart failure patients with chronic pacing leads in the LV. Rademakers et al 9 observed thromboembolic complications with endocardial pacing; however, the risk seemed to be strongly correlated with a subtherapeutic level of anticoagulation. Interestingly, endocardial pacing did not aggravate mitral regurgitation in these patients. Preliminary results from the ALSYNC (ALternate Site Cardiac ResYNChronization) study, which used the same techniques and delivery system demonstrated here, indicate that implantation of an LV endocardial pacing system is feasible, safe, and clinically successful. 10 However, long-term follow-up data are needed to assess the long-term safety and efficacy of this approach to LV pacing/CRT. In this case study, direct visualization aided in LV endocardial lead placement and demonstrated the feasibility of a novel LV endocardial lead delivery system. There was no impingement on the chordae tendineae or leaflets when the lead was placed across the mitral valve; however, the lead may be more difficult to position as precisely as when fluoroscopy is used in the clinical setting. Although placement of an LV lead using direct visualization is not representative of the visualization techniques available in a clinical setting, the images presented here have notable educational value for both clinicians and design engineers.

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          Left ventricular endocardial stimulation for severe heart failure.

          Biventricular resynchronization, a therapy recommended for patients presenting with left ventricular (LV) dysfunction and ventricular dyssynchrony, requires the implantation of an LV lead, usually placed in a lateral or posterolateral tributary of the coronary sinus. Despite important progress made in the development of dedicated instrumentation, the procedure remains sometimes challenging and unsuccessful in a minority of patients. In the rare instances of unsuccessful transvenous implantations occurring in the presence of major surgical contraindications, a few operators have implanted the LV lead transseptally, an approach limited by technical difficulties and by the thromboembolic risk associated with the presence of a lead inside the LV cavity. The interest in this approach was recently renewed by 2 studies in an animal model and in humans, respectively, which both found a distinctly superior hemodynamic performance associated with endocardial compared with epicardial stimulation. This review discusses the advantages and disadvantages of LV endocardial stimulation, examines the various techniques of LV endocardial stimulation, and projects their future applications in light of these highly promising recent results. The implementation of endocardial stimulation will ultimately depend on: 1) the development of safe, effective, and durable instrumentation, and reliable and reproducible intraprocedural methods to identify the optimal site of stimulation; and 2) the completion of controlled trials confirming the superiority of this technique compared with standard cardiac resynchronization therapy. Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
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            Comparison of chronic biventricular pacing between epicardial and endocardial left ventricular stimulation using Doppler tissue imaging in patients with heart failure.

            In patients with a wide QRS, drug-resistant heart failure, and a coronary sinus that is unsuitable for transvenous biventricular pacing (BVP), a transseptal approach from the right to left atrium can allow endocardial left ventricular (LV) pacing (with permanent anticoagulant therapy) instead of epicardial pacing via the coronary sinus branches. We sought to compare the effects of endocardial pacing with those of epicardial LV pacing on regional LV electromechanical delay (EMD) and contractility. Twenty-three patients (68 +/- 8 years) with severe heart failure and QRS > or =130 ms received a pacemaker for BVP. Fifteen patients underwent epicardial LV pacing, and 8 underwent endocardial LV pacing because of an unsuitable coronary sinus. All LV leads were placed at the anterolateral LV wall. Six months after implant, echocardiography and Doppler tissue imaging were performed. LV wall velocities and regional EMDs (time interval between the onset of the QRS and local ventricular systolic motion) were calculated for the 4 LV walls and compared for each patient between right ventricular (RV) and BVP. The amplitude of regional LV contractility was also assessed. Epicardial BVP reduced the septal wall EMD by 11% versus RV pacing (p = 0.05) and the lateral wall EMD by 41% versus RV pacing (p <0.01). With endocardial BVP, the septal and lateral EMDs were 21.3% and 54%, respectively (p <0.01, compared with epicardial BVP). The mitral time-velocity integral increased by 40% with endocardial BVP versus 2% with epicardial BVP (p <0.01). The amplitude of the lateral LV wall systolic motion increased by 14% with epicardial BVP versus 31% with endocardial BVP (p = 0.01). This resulted in a LV shortening fraction increase of 25% in patients with endocardial BVP (p = 0.05). However, all patients were clinically improved at the end of follow-up. Thus, in heart failure patients with BVP, endocardial BVP provides more homogenous intraventricular resynchronization than epicardial BVP and is associated with better LV filling and systolic performance.
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              Mid-term follow up of thromboembolic complications in left ventricular endocardial cardiac resynchronization therapy.

              Endocardial left ventricular (LV) pacing for cardiac resynchronization therapy (CRT) has been proposed as an alternative to traditional LV transvenous epicardial pacing with equal or superior cardiac performance. The risks of cerebral thromboembolism and possible interference with mitral valve function moderate its clinical application.
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                Author and article information

                Contributors
                Journal
                HeartRhythm Case Rep
                HeartRhythm Case Rep
                HeartRhythm Case Reports
                Elsevier
                2214-0271
                23 April 2015
                May 2015
                23 April 2015
                : 1
                : 3
                : 107-109
                Affiliations
                [* ]Medtronic, Inc, Minneapolis, Minnesota
                []Departments of Surgery, Biomedical Engineering, and Integrative Biology & Physiology, and the Institute for Engineering in Medicine, University of Minnesota, Minneapolis, Minnesota
                Author notes
                [* ] Address reprint requests and correspondence: Dr. Paul A. Iaizzo, University of Minnesota, Department of Surgery, B172 Mayo, MMC 195, 420 Delaware St SE, Minneapolis, MN 55455 iaizz001@ 123456umn.edu
                Article
                S2214-0271(15)00003-2
                10.1016/j.hrcr.2015.01.001
                5426419
                2fce518b-71f4-4ed2-974f-9a2b7df652bd
                © 2015 Heart Rhythm Society. Published by Elsevier Inc.

                This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

                History
                Categories
                Case Report

                crt, cardiac resynchronization therapy,la, left atrium,lv, left ventricle,rf, radiofrequency,transseptal puncture,cardiac resynchronization therapy,isolated heart,left ventricular pacing,endocardial pacing

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