title: Direct visualization of coronary sinus ostium and branches with a flexible steerable fiberoptic infrared endoscope.
abstract: BACKGROUND
  Placement of electrophysiology catheters and pacing leads in the coronary sinus is challenging in some patients, particularly those with dilated cardiomyopathy. We hypothesized that cannulation of the coronary sinus and its branches can be facilitated by direct visualization. This study reports our experience with navigation into and within the coronary sinus in a closed-chest animal preparation, using a flexible steerable fiberoptic infrared endoscope that allows visualization through flowing blood.
  
  
  OBJECTIVE
  The purpose of this study was to assess the feasibility of direct visualization of endocardial structures through infrared endoscopy.
  
  
  METHODS
  Internal jugular venous access was obtained in 10 healthy mongrel dogs (weight 35-45 kg). The infrared endoscope (2900 fiber imaging bundle, wavelength 1,620 nm, frame rate 10-30/s, 320 x 256 pixels) was advanced to the coronary sinus ostium and branches by direct visualization of anatomic landmarks, such as the tricuspid valve and inferior vena cava. Localization was confirmed by fluoroscopy, contrast injection, and pathologic examination.
  
  
  RESULTS
  Structures such as the tricuspid valve and inferior vena cava were visualized at distances of 1 to 2 cm, allowing successful coronary sinus identification and engagement in all 10 dogs. Coronary sinus branch images closely resembled pathologic findings.
  
  
  CONCLUSIONS
  Direct visualization of the coronary sinus ostium and branches is possible through infrared endoscopy. This technique likely will facilitate coronary sinus engagement and navigation for pacing lead and catheter placement.
authors.affiliation: Division of Cardiology, Johns Hopkins Hospital, Baltimore, Maryland 21287, USA. snazari1@jhmi.edu
authors.forename: Saman
authors.initials: S
authors.lastname: Nazarian
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Knight
authors.forename: Timm L
authors.initials: TL
authors.lastname: Dickfeld
authors.forename: Menekhem M
authors.initials: MM
authors.lastname: Zviman
authors.forename: Venku B
authors.initials: VB
authors.lastname: Jayanti
authors.forename: David
authors.initials: D
authors.lastname: Amundson
authors.forename: John
authors.initials: J
authors.lastname: Hanlin
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Castleberry
authors.forename: Mark F
authors.initials: MF
authors.lastname: Smith
authors.forename: Larry
authors.initials: L
authors.lastname: Blankenship
authors.forename: Henry R
authors.initials: HR
authors.lastname: Halperin
authors.forename: T Bruce
authors.initials: TB
authors.lastname: Ferguson
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Berger
mesh_terms: D017546:Angioscopy / Q000379:methods*; D000818:Animals; D006328:Cardiac Catheterization; D004285:Dogs; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation*; D019723:Endoscopes; D005240:Feasibility Studies; D005336:Fiber Optic Technology; D007259:Infrared Rays; D014261:Tricuspid Valve / Q000502:physiology*; D014682:Vena Cava, Inferior / Q000502:physiology*