Direct visualization of coronary sinus ostium and branches with a flexible steerable fiberoptic infrared endoscope

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. Objectives: 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 × 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 suc has 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. Conclusion: 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.