title: Lead fixation in dogs achieved with RF energy.
abstract: BACKGROUND
  The purpose of this study was to test whether radiofrequency (RF) energy could be used to fixate leads to the endocardium.
  
  
  RESULTS
  In six dogs we measured the dislodgment force and pacing threshold before and after RF fixation in the coronary sinus (CS) and right ventricle (RV). RF fixation was achieved with a CardioRhythm Atakr ablation unit. The dislodgment force of CS leads fixed with RF energy was 1.63+/-0.65 oz, compared with < 0.1 oz for similar leads placed in the CS of six separate dogs. In the RV, leads fixed with RF energy had a dislodgment force of 1.29+/-0.27 oz, compared with 0.48+/-0.28 oz. for urethane (P < 0.01) and 1.01+/-0.21 oz for silicone (P = 0.41) tined leads. In the CS, the pacing threshold for RF fixed leads increased significantly from 2.2+/-1.1 V (0.5 msec) before fixation to 4.2+/-1.3 V after fixation (P < 0.01), while in the RV, the pacing threshold increased from 0.41+/-0.05 V (0.5 msec) before fixation to a mean of 2.03+/-0.44 V after fixation (P < 0.01). In another group of six dogs studied for 12 weeks, 5 of 6 RF fixed CS leads remained attached, as did 8 of 10 RF fixed RV leads. For the RV leads, the mean pacing threshold was 0.90+/-0.35 V, compared with 0.53+/-0.18 V (0.5 msec) for similar tined leads (P = 0.02) and 1.2+/-0.30 V (0.5 msec) for screw leads (P = 0.18) in the RV.
  
  
  CONCLUSIONS
  We conclude that RF energy can be used to attach leads to the RV and CS endocardium. While the RV pacing thresholds increased acutely, the mean chronic thresholds were not significantly different for RF fixed leads and standard tined or screw leads.
authors.affiliation: Medtronic Inc., Tachyarrhythmia Research, Minneapolis, Minnesota, USA.
authors.forename: M
authors.initials: M
authors.lastname: Bonner
authors.forename: R
authors.initials: R
authors.lastname: Mehra
authors.forename: D P
authors.initials: DP
authors.lastname: Zipes
mesh_terms: D000818:Animals; D017115:Catheter Ablation; D017147:Defibrillators, Implantable; D004285:Dogs; D004566:Electrodes; D004594:Electrophysiology; D004699:Endocardium; D005240:Feasibility Studies; D006352:Heart Ventricles; D008722:Methods; D010138:Pacemaker, Artificial; D011846:Radio Waves; D000267:Tissue Adhesions