Lead placement

Herman MV, Ingram DA, Levy JA et al. Variability of electrocardiographic precordial lead placement a method to improve accuracy and reliability. Clin Cardiol 1991 14 469. 

CRT reduces symptoms of CHF and improves cardiac performance in patients with moderate-to-severely symptomatic heart failure, severe left ventricular systolic dysfunction, normal sinus rhythm and a wide QRS complex. Resynchronization therapy significantly reduces hospitalizations in these patients and is highly cost-effective. Perhaps most important, resynchronization therapy for heart failure improves survival for these patients, particularly when employed in conjunction with an implantable defibrillator. However, randomized clinical trials show that a substantial minority of patients are clinical nonresponders. Therefore, critical questions remain with respect to identifying appropriate candidates for CRT, optimal device programming, and left ventricular lead placement. 

Another major breakthrough in lead design is the steroid-eluting electrode (Figure 11.12). About 1 mg of a corticosteroid (dexamethasone sodium phosphate) is contained in a silicone core that is surrounded by the electrode material. The leaking of the steroid into the myocardium occurs slowly over several years and reduces the inflammation that results from the lead placement. It also retards the growth of the fibrous sack that forms around the electrode, which separates it from viable myocardium. As a result, the dramatic rise in acute thresholds that is seen with nonsteroid leads during the 8-16 weeks postimplant is nearly ehminated. 

Worley SJ, Gohn DC, Pulliam RW (2008) Focused force coronary venoplasty to eliminate a refractory stenosis preventing LV lead placement in two patients. Pacing Clin Electrophysiol 31(11) 1503-1505... 

Once successful ventricular lead placement has been achieved, the lead must be secured. The first step in this process is withdrawal of the lead stylet to the vicinity of the lower right atrium (89) (Fig. 4.38). The stylet is not totally removed, but retained to add support if a second lead is to be placed. With a straight ventricular lead stylet in the vicinity of the lower right atrium, the lead is anchored at the venous entry site. The lead suture sleeve should be used for anchoring to avoid lead injury. Care is also taken not to cut through the suture sleeve and also injure the lead. Once the ventricular lead is anchored and after no further leads are to be added, the lead stylet is removed. 

Atrial lead placement directly relates to the type of atrial electrode selected, regardless of fixation mechanism. Similar to the ventricular lead, proper placement is a symphony of the lead and stylet. 

The floppy-tip technique may be used for achieving unusual atrial lead placement with a shaight active fixation lead. This is particularly useful for placement along the right lateral atrial wall. With the curved stylet retracted 1 to 2 in., the lead tip assumes a more lateral position. By simply advancing the lead to a point of contact, the fixation mechanism can be activated and threshold measurements carried out. 

Unlike ventricular lead placement, venous access has little effect on atrial lead positioning. Whether from the right or left venous access, the preformed J or straight electrode with preformed J stylet is easily maneuvered into the atrial appendage or desired position. It should be noted that a right lateral atrial position is more easily achieved by a right venous access. Atrial septal positions are more easily achieved from the left. 

Fig. 4.64 Lateral view demonstrating transhepatic lead placement. (Fishberger SB, Camunas J, Rodriguez-Femandez H, et al. Permanent pacemaker lead implantation via the transhepatic route. Pacing Chn Electrophysiol 1996 19(7) 1124-1125, with permission.)...

Fig. 4.68 Atrial lead placement through atriotomy and purseslring suture. Atrium and ventricular electrodes are positioned and the atriotomy is secured. (Westerman GR, Van Devanter SH. Transthoracic transatrial endocardial lead placement for permanent pacing. Ann Thorac Surg 1987 43(4) 445-446, with permission.)...

Fig. 4.69 Atrial lead placement. Insert in the upper right shows atrial endocardial lead being placed through the wall of the right atrial appendage with the tip of the pacemaker lead abutting the endocardial surface. A pursestring suture is placed around the lead at the point of entry. The relationship of the atrial lead is also shown. (Hayes DL, Vhetstra RE, Puga FJ, et al. A novel approach to atrial endocardial pacing. Pacing Clin Electrophysiol 1989 12(1 Pt 1) 125-130, with permission.)...

Table 4.14 Endocardial approaches for coronary sinus left ventricular lead placement.

After venous access, some consideration should be given to the sequence of lead placement. Some operators prefer to place the RV electrode first for emergency RV pacing, should heart block ensue because the heart failure patients commonly have a left bundle branch block and any trauma to the conduction system or right bundle may result in complete heart block. Other operators choose to place the coronary sinus lead first and, if necessary, depend on heart rate support via a temporary transvenous pacemaker placed via the femoral vein. The issue of failure speaks for placing the coronary sinus lead first. Should the procedure fail with unsuccessful left-sided left ventricular lead placement and the patient has already received right-sided electrodes, a pacing system may be left without an indication unless a future second attempt is considered. As more and more systems are placed for a primary prevention indication like MADIT II, this has become less problematic (153). 

Fig. 4.88 A. Guide wire passed into a posterolateral branch of the CS. B. Example of the various angioplasty guide wires for use in over the wire lead placement (from Belott PH Implantation Techniques for Cardiac resynchronization Therapy Barold SS, Mugica J Fifth Decade of Cardiac Pacing. Armonk NY Futura. 2004 pp 18)...

Recently, thoracoscopic approaches, less risky than thoracotomy, have been developed for the placement of left ventricnlar leads (155-157). Still to be resolved are the issues of lead instabihty and unreliable sensing and pacing characteristics. On the horizon, with respect to an epicardial approach, is a percntaneons technique utilizing robotics for left-sided lead placement. 

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