title: Initial clinical experience with cardiac resynchronization therapy utilizing a magnetic navigation system.
abstract: BACKGROUND
  The placement of left ventricular (LV) leads during cardiac resynchronization therapy (CRT) involves many technical difficulties. These difficulties increase procedural times and decrease procedural success rates.
  
  
  RESULTS
  A total of 50 patients with severe cardiomyopathy (mean LV ejection fraction was 21 +/- 6%) and a wide QRS underwent CRT implantation. Magnetic navigation (Stereotaxis, Inc.) was used to position a magnet-tipped 0.014'' guidewire (Cronus guidewire) within the coronary sinus (CS) vasculature. LV leads were placed in a lateral CS branch, either using a standard CS delivery sheath or using a "bare-wire" approach without a CS delivery sheath. The mean total procedure time was 98.1 +/- 29.1 minutes with a mean fluoroscopy time of 22.7 +/- 15.1 minutes. The mean LV lead positioning time was 10.4 +/- 7.6 minutes. The use of a delivery sheath was associated with longer procedure times 98 +/- 32 minutes vs 80 +/- 18 minutes (P = 0.029), fluoroscopy times 23 +/- 15 minutes vs 13 +/- 4 minutes (P = 0.0007) and LV lead positioning times 10 +/- 6 minutes vs 4 +/- 2 minutes (P = 0.015) when compared to a "bare-wire" approach. When compared with 52 nonmagnetic-assisted control CRT cases, magnetic navigation reduced total LV lead positioning times (10.4 +/- 7.6 minutes vs 18.6 +/- 18.9 minutes; P = 0.005). If more than one CS branch vessel was tested, magnetic navigation was associated with significantly shorter times for LV lead placement (16.2 +/- 7.7 minutes vs 36.4 +/- 23.4 minutes; P = 0.004).
  
  
  CONCLUSIONS
  Magnetic navigation is a safe, feasible, and efficient tool for lateral LV lead placement during CRT. Magnetic navigation during CRT allows for control of the tip direction of the Cronus 0.014'' guidewire using either a standard CS delivery sheath or "bare-wire" approach. Although there are some important limitations to the 0.014'' Cronus magnetic navigation can decrease LV lead placement times compared with nonmagnetic-assisted control CRT cases, particularly if multiple CS branches are to be tested.
authors.affiliation: Central Baptist Hospital, Lexington, Kentucky, USA. pgallagher@lexingtoncardio.com
authors.forename: Peter
authors.initials: P
authors.lastname: Gallagher
authors.forename: Laura
authors.initials: L
authors.lastname: Martin
authors.forename: Lori
authors.initials: L
authors.lastname: Angel
authors.forename: Gery
authors.initials: G
authors.lastname: Tomassoni
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D009202:Cardiomyopathies / Q000628:therapy*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D016896:Treatment Outcome