title: 3D cardiovascular navigation system: accuracy and reduction in radiation exposure in left ventricular lead implant.
abstract: BACKGROUND
  Cardiac resynchronization therapy implants entail significant radiation exposure for patients and physicians. A novel 3D electromagnetic cardiovascular navigation system (MediGuide™) was designed to superimpose the real-time location of sensors embedded in delivery tools on prerecorded coronary sinus (CS) venograms while adjusting for patient movement and variations in heart rate under different C-arm angulations. We studied the accuracy and efficacy of MediGuide™ in reducing radiation exposure during LV lead implants.
  
  
  RESULTS
  Fluoroscopy durations and radiation exposures were measured in 6 canines undergoing both conventional and MediGuide™-guided LV lead implants. The in vivo accuracy of MediGuide™ was evaluated by obtaining CS venograms at 3 different C-arm angulations at 3 different heart rates and measuring the separation between the projected sensor icon of a MediGuide™ sensor-enabled guidewire and the encompassing branch on prerecorded venograms.
  
  
  RESULTS
  Mediguide™-guided implants resulted in significant reductions in fluoroscopy time (52 ± 120 [median 6] vs 129 ± 118 [median 90] sec, P < 0.001) and radiation exposure (13.8 ± 32.4 [median 1.7] vs 49.2 ± 45.3 [median 27.2] μGym(2) , P = 0.03) compared to conventional implants. LV lead delivery time was not significantly different between the 2 implant techniques (P = 0.27). The mean separation between the projected guidewire sensor icon and its encompassing branch was 0.48 ± 0.94 (median 0.00) mm. System accuracy was not affected by variations in heart rate or C-arm angulations.
  
  
  CONCLUSIONS
  The novel 3D cardiovascular navigation system enabled accurate and reliable tracking of sensor-enabled tools at varying heart rates and C-arm angulations with minimal need for fluoroscopy guidance, significantly reducing fluoroscopy time and radiation exposure.
authors.affiliation: The Methodist Hospital System, Houston, Texas, USA.
authors.forename: Miguel
authors.initials: M
authors.lastname: Valderrabano
authors.forename: Steven
authors.initials: S
authors.lastname: Greenberg
authors.forename: Hedi
authors.initials: H
authors.lastname: Razavi
authors.forename: Rohan
authors.initials: R
authors.lastname: More
authors.forename: Kyungmoo
authors.initials: K
authors.lastname: Ryu
authors.forename: E Kevin
authors.initials: EK
authors.lastname: Heist
mesh_terms: D000818:Animals; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods*; D017147:Defibrillators, Implantable / Q000009:adverse effects; D004285:Dogs; D005260:Female; D005471:Fluoroscopy / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D008297:Male; D011829:Radiation Dosage
keywords: LV lead; MediGuide; cardiac resynchronization therapy; electromagnetic navigation; radiation exposure