Biventricular resynchronization therapy is recommended for patients presenting with left ventricular (LV) dysfunction and ventricular dyssynchrony. Cardiac resynchronization therapy requires the implantation of an LV lead, usually placed in a lateral or posterolateral tributary of the coronary sinus .
Implantation of a left ventricular (LV) lead fails in 5% to 10% of patients in whom cardiac resynchronization therapy (CRT) is attempted. Conventional approach is not feasible due to anatomic abnormalities in the CS and its branches or due to high pacing thresholds or phrenic nerve stimulation. In these cases, surgical implantation of a lead onto the LV epicardium via thoracotomy or thoracoscopy is considered the alternative. However, this is a more invasive procedure, which limits its applicability in some patients with very low LV ejection fraction and high anaesthesia risk [2,3].
LV endocardial lead placement allows unrestricted lead positioning for pacing. There is some evidence that LV endocardial pacing may be significantly superior to epicardial pacing, providing more a physiological and effective contraction of the heart muscle. This may improve response to CRT, and potentially provide response to the therapy in patients who have previously not responded to conventional CRT .
2. Case presentation
We present a case of a 62 year, old male who was complaining of dyspnea, NYHA Class III/IV. He was admitted to national heart institute, Egypt, with severe LV dysfunction due to ischemic cardiomyopathy. He had history of surgical coronary revascularization in 2006 with retrograde cardioplegia then percutaneous coronary intervention in 2015 to native vessels due to graft failure. His echocardiography showed ischemic dilated cardiomyopathy with poor LV systolic function, ejection fraction 20%, and mild MR. 12 leads ECG showed LBBB with QRS duration of 130 ms.
His medical history included chronic kidney disease with serum creatinine during admission 1.6 Mg/dl.
Patient was prepared in the standard manner for CRT implantation (Viva™ CRT-P, Medtronic, MN, USA) by adjusting patient volume status, anti-staphylococcal agents (1 g flucloxacillin IV at or ½ h before implantation and reviewing patient's coagulation profile and investigations. (Venous access was gained using the Seldinger technique to the left subclavian vein. Thereafter, right atrial and right ventricular pacing leads were implanted in a conventional manner by advancing the leads through “Peel Away” sheaths in their subclavian accesses to right atrium and right ventricle respectively. During that procedure, the right ventricular lead was implanted in the apex. LV lead implantation was tried many times, which was unsuccessful due to vertically oriented coronary sinus anatomy and unusual multiple stenosis of coronary sinus (CS) may be due to previous retrograde cardioplegia as shown in (Fig. 1).
Epicardial lead was discussed with the patient and he refused. So informed consent was taken to implant the LV lead via transseptal approach. Right femoral artery was punctured via a 6F introducer and pig tail catheter was introduced to land mark the aortic root. An access was obtained to the right femoral vein via a standard introducer and standard transseptal sheath was introduced in the left atrium from the right femoral vein followed by an intravenous injection of 5000 international units of heparin. A 4 cm long 8 mm angioplasty balloon was inserted into the left atrium (LA) and positioned and inflated across the septal puncture site (Fig. 2). Hereafter a steerable (Agilis™, Abbott, USA) introducer with dilator was introduced through the left subclavian vein. The steerable introducer was used to negotiate passing the septostomy site with help of decapolar catheter into the LA through the atrial septum. A guidewire was positioned within the LA, the Agilis steerable introducer was exchanged for a straight slittable CS delivery sheath. Double-coil wire (Inoue™ metal wire, Toray, Japan) was introduced through the mitral valve which is more supportive to pass the Cs delivery sheath over it. Then, CS delivery sheath was positioned in the LV at the posterolateral area.
A standard RV bipolar active fixation lead (Medtronic, MN, USA) was subsequently implanted through the deflectable sheath in the posterolateral area (Fig. 3). LV sensed R wave was 8 mV, LV pacing threshold 1.5 V at impulse width of 0.5 ms, and mean LV lead impedance 670 Ω. Stimulation with 10.0 V did not result in phrenic nerve stimulation. Biventricular pacing was present as shown in 12 leads ECG after CRT implantation (Fig 4).
Anticoagulant therapy with warfarin was instituted immediately after the procedure with target INR 2-3. Echocardiographic examination was done after implant showed no increase in mitral regurgitation, There was no a transseptal shunt, pericardial fluid, or any other complication. Patient was followed up After 3 and 6 months, sensing and pacing parameters have remained stable, there have not been clinical signs of thromboembolic events and patient has improved his functional class.
We describe a successful transseptal implantation of a LV lead in a patient with failed transvenous CS implant. Cardiac resynchronization therapy is well established as a treatment for heart failure in patients with severely impaired LV systolic function and evidence of ventricular dyssynchrony. The conventional access to CS limited by technical considerations (phrenic nerve stimulation and poor pacing characteristics) and the anatomy of the coronary venous system.
Direct LV endocardial pacing has been reported previously. This has been achieved either inadvertently or by employing a specific directed LV endocardial pacing approach [5,6]. There is also an experience of direct transaortic pacing in an animal model using polyurethane-constructed pacing leads, which has been associated with no embolic complications . The use of the steerable guide catheter and the ability to precisely orientate pacing lead placement offers a controlled and targeted approach to LV endocardial pacing. Endocardial LV lead placement via a transseptal approach is a novel alternative approach for LV pacing in CRT. However, up to now there is not a standardized approach because the implant techniques described to date are technically difficult [6,8].
In our case there is no need for general anesthesia and there is minimum postoperative recovery. In comparison to epicardial pacing, endocardial LV stimulation has some potential advantages. The transseptal access allows a broader choice for the pacing site inside the LV cavity and is not limited by the anatomy of the tributary veins of the CS. high pacing threshold, the lead can be repositioned to a different site inside the LV cavity, this is often difficult when maneuvering the lead in the cardiac venous system . The risk for phrenic nerve stimulation is low. In our case no phrenic nerve stimulation occurred at high energy stimulation and optimal implantation and follow-up electrical parameters were observed.
We describe the implantation of endocardial LV lead through a left subclavian access after doing transseptal puncture through femoral vein. Further development of dedicated tools for use during implantation will allow the implant procedure to be further widespread. Guidelines should be developed to unify procedure steps and determine the use of this approach in specific patient groups.
6. Conflict of interests
No conflict of interests.
 Ponikowski P, Voors AA, Anker SD, Bueno H, Cleland JG, Coats AJ, et al. 2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: The Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC) Developed with the special contribution of the Heart Failure Association (HFA) of the ESC. Eur Heart J 2016 Jul 14;37(27):2129-2200.
 Mair H, Jansens JL, Lattouf OM, Reichart B, Dabritz S. Epicardial lead implantation techniques for biventricular pacing via left lateral mini-thoracotomy, video-assisted thoracoscopy, and robotic approach. Heart Surg Forum 2003;6:412-417.
 Gabor S, Prenner G, Wasler A, Schweiger M, Tscheliessnigg KH, Smolle-Jüttner FM. A simplified technique for implantation of left ventricular epicardial leads for biventricular re-synchronization using video-assisted thoracoscopy (VATS). Eur J Cardiothorac Surg 2005;28:797-800.
 Cazeau S, Leclercq C, Lavergne T, Walker S, Varma C, Linde C, et al. Effects of multisite biventricular pacing in patients with heart failure and intraventricular conduction delay. N Engl J Med 2001;344:873-880.
 Van Gelder BM, Bracke FA, Oto A, Yildirir A, Haas PC, Seger JJ, et al. Diagnosis and management of inadvertently placed pacing and ICD leads in the left ventricle: a multicenter experience and review of the literature. Pacing Clin Electrophysiol 2000;23:877-883.
 Van Gelder BM, Scheffer MG, Meijer A, Bracke FA. Transseptal endocardial left ventricular pacing: an alternative technique for coronary sinus lead placement in cardiac resynchronization therapy. Heart Rhythm 2007;4:454-460.
 Reinig M, White M, Levine M, Cha R, Cinel I, Purnachandra J, et al. Left ventricular endocardial pacing: a transarterial approach. Pacing Clin Electrophysiol 2007;30:1464-1468.
 Kutyifa V, Merkely B, Szilágyi S, Zima E, Róka A, Király A, et al. Usefulness of electroanatomical mapping during transseptal endocardial left ventricular lead implantation. Europace 2012;4:599-604.
 Neuhoff I, Szilágyi S, Molnár L, Osztheimer I, Zima E, Dan GA, et al. Transseptal leftventricular endocardial pacing is an alternative technique in cardiac resynchronization therapy. One year experience in a high volume center. Rom J Intern Med. 2016;54(2):121-128.