Measurement of Tip Load With a Pacemaker Lead Stylet and Guiding Catheter Using a Silicone Heart Model

Background Ventricular septal pacing has long been performed using a stylet during pacemaker implantation, but with the availability of guiding catheters, His bundle pacing and left bundle branch area pacing have also been performed. However, it is not known to what extent the tip load of the ventricular lead differs when a guiding catheter is used compared with a stylet alone. In this study, the tip load was measured for different stylet stiffness and guiding catheter geometries at sites where His bundle pacing and left bundle branch area pacing were assumed. Method A small weighing instrument was placed in the right ventricular septal portion of the silicone heart model to measure the apical load of the ventricular lead when using two types of guiding catheters and three different types of stylets according to stiffness at the site where His bundle pacing and left bundle branch area pacing were assumed. Results The guiding catheter group had by far the highest tip load compared to the stylet group (Site Selective Pacing Catheter (SSPC) multipurpose group 17.9 ± 1.6 g, SSPC extended hook group 3.6 ± 0.8 g). There was no significant difference in tip load between His bundle pacing site and the left bundle branch area pacing site for the normally used stiffness stylet. Conclusions Guiding catheters are used for conduction system pacing but must be used with great care as they apply a much greater tip load than conventional lead placement with a stylet alone.