In vivo angioscopic visualization of right heart structure in dogs by means of a balloon-tipped fiberoptic endoscope: Potential role in percutaneous ablative procedures

We designed an angioscopic system that consisted of a fiberoptic endoscope enclosed in a polyurethane thin-wall tube with a latex balloon attached to its distal end. In 10 anesthetized closed-chest dogs the angioscope was placed in the right heart via a femoral vein. By inflating the balloon with 5 to 10 ml of normal saline solution to displace the blood, the endocardial structure of the right heart was visualized. Under fluoroscopic guidance and direct vision, an ablation catheter was placed inside the coronary sinus or in its vicinity, and radiofrequency energy was delivered through the catheter tip to create a lesion. The appearance and anatomic location of the lesion and the endocardial structure as seen through the angioscope correlated well with the results of postmortem examination. There were no or minimal changes in heart rate, blood pressure, or cardiac output by inflating the balloon to a volume of 15 ml in the right atrium or right ventricular cavity. An inflated balloon may produce single or repetitive atrial or ventricular arrhythmias, but not sustained tachyarrhythmia. Our study demonstrates that in vivo visualization of the interior of the right heart is feasible and that our angioscope can be used to assist placement of catheter at a specific location in the right atrium and to verify its location with no or minimal hemodynamic effects and without causing significant arrhythmias.