Phrenic nerve stimulation with LV lead in CRT

Phrenic nerve stimulation with LV lead in CRT

Phrenic nerve stimulation is an important adverse effect which can occur during left ventricular pacing through a lateral vein in cardiac resynchronization therapy, due to the proximity to phrenic nerve. First response if there is phrenic nerve stimulation with left ventricular lead during implantation of cardiac resynchronization therapy is to try another vein. Another way is to try bipolar stimulation, deeper in a vein. Stimulation deeper in a vein can produce ventricular ectopy, which usually resolves in a few days. Bipolar stimulation is less likely to produce phrenic nerve stimulation. Direct diaphragmatic stimulation should also be considered, rather than phrenic nerve stimulation.

Another method is to go in for an epicardial implantation. During surgical implantation, it is possible to pull the phrenic nerve away and even anchor it a different site. While checking for diaphragmatic pacing during epicardial pacing, muscle relaxants should be withdrawn prior to checking for diaphragmatic stimulation. Same applies to implantation in the cath lab under general anaesthesia.