title: Long-term performance of active-fixation pacing leads: a prospective study.
abstract: BACKGROUND
  Despite the increasingly widespread use of active-fixation leads, long-term clinical follow-up of pacing lead outcomes is lacking. The aim was to analyze pacing parameters over a 2-year follow-up. We performed a prospective observational study of consecutive new pacemaker implants using the 1488T St. Jude (100) and the Medtronic 5076 (100) active-fixation leads. Detailed analysis of pacing parameters was collected at implant, day 1, and 1, 3, 6, 12, 18, and 24 months.
  
  
  RESULTS
  One hundred patients underwent implantation of 100 dual-chamber pacemakers. Initial pacing parameters in the ventricle were threshold 0.7 +/- 0.2 V, R wave 12.0 +/- 6.5 mV, and impedance 879 +/- 224 Omega. Threshold increased significantly from day 1 (0.7 +/- 0.2 V) to month 1 (0.9 +/- 0.6 V, P < 0.01) and remained stable over the long term. Four of the 100 patients had a threshold >2 V (mean 3.3 +/- 0.9 V) all between day 1 and month 3. For all patients, R wave remained stable, but impedance declined significantly from day 1 (879 +/- 184 Omega) to month 1 (677 +/- 122 Omega, P < 0.01). There were no ventricular lead complications. Initial pacing parameters in the atrium were threshold 0.9 +/- 0.3 V, P wave 3.3 +/- 2.4 mV, and impedance 606 +/- 144 Omega. Threshold remained stable over the long-term follow-up. One of 100 patients had a rise in threshold >2 V (2.2 V) between day 1 and month 1. No patients underwent lead repositioning. Sensing and impedance remained stable over the long term. Patient follow-up was completed in 94% (6 unrelated deaths). There was an 8% incidence of atrial fibrillation.
  
  
  CONCLUSIONS
  Active-fixation leads are generally associated with stable long-term pacing parameters.
authors.affiliation: Department of Cardiology, The Royal Melbourne Hospital, Parkville, Victoria, 3050, Australia.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Kistler
authors.forename: Gary
authors.initials: G
authors.lastname: Liew
authors.forename: Harry G
authors.initials: HG
authors.lastname: Mond
mesh_terms: D001315:Australia / Q000453:epidemiology; D002304:Cardiac Pacing, Artificial / Q000706:statistics & numerical data*; D004567:Electrodes, Implanted; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010138:Pacemaker, Artificial / Q000706:statistics & numerical data*; D011446:Prospective Studies; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000453:epidemiology* / Q000628:therapy*