title: Left ventricular lead performance in cardiac resynchronization therapy: impact of lead localization and complications.
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) using left ventricular (LV) pacing from the coronary sinus tributary is increasingly and frequently used in patients with severe congestive heart failure. The present study investigates LV lead performance in different anatomic locations.
  
  
  METHODS
  The LV pacing site was defined by bi-plane fluoroscopy. In the left anterior oblique view, the coronary sinus is encircling the mitral ring with the tributaries radiating out like the hands of a watch. Using this clockwise method, Group A had an LV pacing site before 3 o'clock and Group B at or after 3 o'clock. In right anterior oblique view, the LV was divided into three segments: basal, mid-ventricular, and apical.
  
  
  RESULTS
  LV lead implantation was successful in all of 120 consecutive patients. Mean follow-up was 16.7 months. Implantation time decreased from mean 190 to 80 minutes during the period (P = 0.01). The mean LV lead stimulation threshold increased initially and stabilized afterwards. The threshold measured at last follow-up was higher than at implantation (2.3 vs 2.7 microJ, P = 0.04). Useful venograms were obtained in 94 patients. No significant difference in thresholds was observed between Groups A and B. Phrenic nerve stimulation was most commonly seen in Group B (8/70 vs 1/24, P = 0.001).
  
  
  CONCLUSIONS
  Implantation of an LV lead for CRT is possible in patients with congestive heart failure and associated with an acceptable low complication rate. LV lead implantation is associated with a learning curve. At mid-term follow-up, LV lead performance is stable and unrelated to the LV implantation site.
authors.affiliation: Department of Cardiology, Aarhus University Hospital (Skejby), Brendstrupgaardsvej, DK-8200 Aarhus N, Denmark. andieie@mail.dk
authors.forename: Andi Eie
authors.initials: AE
authors.lastname: Albertsen
authors.forename: Jens Cosedis
authors.initials: JC
authors.lastname: Nielsen
authors.forename: Anders Kirstein
authors.initials: AK
authors.lastname: Pedersen
authors.forename: Peter Steen
authors.initials: PS
authors.lastname: Hansen
authors.forename: Henrik Kjaerulf
authors.initials: HK
authors.lastname: Jensen
authors.forename: Peter Thomas
authors.initials: PT
authors.lastname: Mortensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D017147:Defibrillators, Implantable; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged