Cardiac Resynchronization Therapy - How to Overcome High Left Ventricular Pacing Thresholds and Avoid Phrenic Nerve Stimulation

Abstract

High pacing thresholds and phrenic nerve stimulation (PNS) are not uncommon in contemporary cardiac resynchronization therapy (CRT) systems, based on our own experience as well as on other series. Whereas some cases may be resolved by programming, other cases necessitate reoperations or abandonment of the left ventricular (LV) lead. Approaches to avoid and to manage these two problems are reviewed according to our experience as divided into four phases: 1) During implantation ??? whereby careful selection of pacing site is required, as well as meticulous testing of thresholds and PNS, and avoidance of any site with any PNS; 2) Device and lead selection ??? in difficult cases with high thresholds and PNS, a system with multiprogrammable pacing configurations and bipolar leads may be preferred; 3)Programming ??? we found a significant advantage of systems with multiprogrammable pacing configurations and bipolar leads in dealing with PNS and high thresholds with essentially nearly 100% of those problems being resolved by reprogramming the pacing configuration in the LV lead; 4) Epicardial implantation ??? in cases where adequate LV pacing cannot be achieved, epicardial pacing should be considered with special emphasis on appropriate lead location.