Utility of Novel Vectors in a Quadripolar Left Ventricular Lead

Abstract

Background Two complications which frequently arise with the use of cardiac resynchronization therapy (CRT) are phrenic nerve stimulation (PNS) and/or high pacing thresholds. These complications often result in costly and invasive surgical procedures required to revise an existing left ventricular (LV) lead in order to provide safe and optimal therapy. Quadripolar (QP) left ventricular leads include four electrically active rings which provide redundancy and allow the prescriber to change pacing configurations and optimize CRT delivery. This capability can also be used to resolve PNS or high pacing threshold by programming a new pacing vector, and thus provides a low-risk alternative to traditional invasive procedures. Objective The goal of this study is to evaluate the utility of seven programmable novel LV pacing vectors which utilize one or both distal rings that are unique to quadripolar LV leads. Methods The analysis was part of a multi-center, prospective, non-randomized study. Novel pacing vector data was collected during a clinic follow-up visit at 3 months post implant for subjects implanted with a BIOTRONIK Sentus QP lead in combination with a BIOTRONIK CRT-D implantable device. Novel vectors contained one or both distal LV rings (LV3 and LV4) and were evaluated via a threshold test at a pulse width of 0.4 ms. LV pacing thresholds ≤ 2.5 V at 0.4 ms were considered acceptable. Results A total of 930 subjects were successfully implanted at 76 U.S. and international sites. Of 662 subjects with available novel data at 3 months post implant, there were 509 subjects who underwent threshold testing of at least four of the seven novel pacing vectors. The percentage of subjects in this group with at least one novel vector with an acceptable LV pacing threshold was 89.2% (N=454). Table 1 provides the number and percentage of subjects for the total novel vectors with an acceptable threshold. Conclusion The results demonstrate an ability to provide alternate novel vector pacing configurations for subjects who may otherwise require an invasive procedure to resolve PNS or high pacing threshold.