Right atrial leads

FIGURE 5.2 Typical PA and lateral chest X-ray after implantation of CRT-D system. Note the course of the LV lead via the coronary sinus to reach the lateral epicardial wall of the left ventricle, which is posterior as viewed in the lateral projection. (RA, right atrial lead with tip in right atrial appendage RV, ICD lead with tip in right ventricular apex LV, left ventricular lead with tip at the mid-lateral wall of the left ventricle.)... 

In many ICD systems, pacing and sensing are hmited to the right ventricle (single-chamber ICDs), and usually, only a single lead is required. More often, a pace-sense lead is also inserted via the same transvenous route and is fixed in the right atrium (dual-chamber ICD). The right atrial lead provides... 

The right atrial lead of a dual chamber ICD. limitations. 

FIGURE I5.I Schematic representation of a dual-chamber ICD. The generator is implanted in the pectoral region. The defibrillation lead (lower) is in the rightventricle, where it is fixed by a helix at the distal (far) end of the lead. The atrial lead (upper) is secured by flexible tines in the right atrial appendage. (Reproduced with permission of Medtronic, Inc.)... 

Lead location Usually, ventricular leads are more resistant to removal than atrial leads because of their tendency to develop adhesions to the tricuspidal valve and ventricular wall [3]. Moreover, atrial tip detachment from the right appendage may be very challenging for the lead... 

The next evolutionary step in atrial lead development was the endocardial active-fixation, screw-in lead. Such leads, even without steroid-elution became popular for right atrial use, with the anticipated high stimulation thresholds and exit block accepted as an inevitable consequence of endocardial trauma (31). It was believed that the incidence of lead dislodgement was lower than with the use of fined passive-fixation leads. As experience was obtained with both systems, the actual incidence of lead dislodgement was found to be very low, with high volume implanters reporting an incidence of 1-4% with no clear preference for either design (31). 

Fig. 4.34 Lead passage from the right side, causing the lead tip to track laterally to the right atrial wall. (From Belott PH. A practical approach to permanent pacemaker implantation. Armonk, NY Futura Publishing, 1995, with permission.)...

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. 4.63 Posterior-anterior abdominal radiograph showing the position of a pacemaker and generator lead inserted into the inferior vena cava using a retroperitoneal approach. (West JN, Shearmann CP, Gammage MD. Permanent pacemaker positioning via the inferior vena cava in a case of single ventricle with loss of right atrial-vena cava continuity. Pacing Clin Electrophysiol 1993 16(8) 1753-1755, 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.)...

With the above considerations, there is need for long-term, randomized studies that include a well-defined patient population and multiple weU-defined pacing sites that evaluate functional hemodynamics, lead stability, extractability, and complication data. Until such time, the right atrial appendage and right ventricular apex, with proven reliability, stability, and simplicity, should not be abandoned. 

Lok NS, Lau CP, Tse HF, Ayers GM. Clinical shock tolerability and effect of different right atrial electrode locations on efficacy of low energy hnman transvenous atrial defibrillation using an implantable lead system. J Am Coll Cardiol 1997 30 1324-30. 

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