Direct in vivo visualization of right cardiac anatomy by fiberoptic endoscopy. Hemodynamic effects and image validation.

The authors tested the ability of a balloon-tipped fiberoptic endoscope to accurately visualize and identify right-heart anatomy in 7 anesthetized dogs. A 3.6-mm-diameter fiberoptic endoscope with a latex balloon covering the distal tip was inserted into the right atrium, where the balloon was inflated with air in 5 mL increments. Heart rate did not show changes. Mean arterial pressure and cardiac output started to show significant decreases with a balloon volume at 25 and 20 mL, respectively (n = 7). Visual image quality was excellent with a balloon volume of 10 mL or greater. With a balloon volume of 7-10 mL, the visual field was 15-20 mm in diameter. Right-heart anatomy including the right free wall, ostium of the coronary sinus, atrioventricular node area, tricuspid valve, right ventricular structures, and pulmonary arteries was clearly and accurately identified. Additionally, spatial relationships among these structures could be established. Furthermore, there was an excellent concordance between endoscopically observed images and postmortem findings. In conclusion, balloon-tipped fiberoptic endoscopy can accurately visualize normal intracardiac structures with no or minimal hemodynamic compromise.