Initial experience with a high-impedance lined endocardial pacemaker lead: Evidence for increased lead failure

We report our initial clinical experience with a new tined ventricular endocardial pacemaker lead, the Medtronic model 5034. This lead has a reduced electrode tip size, which provides a higher impedance. Based on early evidence of elevation of pacing lead threshold, we compared our clinical experience with the performance of this lead with that of other similar models with larger surface area (Medtronic models 4024 and 5024). Of 17 implant procedures performed at our institution with the model 5034 lead, two (11.2%) developed high thresholds, versus 0% in 121 implant procedures with models 4024 or 5024 leads (p = 0.014). We conclude that there is evidence of increased failure caused by elevation of pacing threshold in this lead. This increased failure rate needs to be confirmed in a multicenter observational study or randomized trial.