NONFLUOROSCOPIC GUIDANCE FOR CATHETER PLACEMENT INTO THE CORONARY SINUS UNDER DIRECT VISION USING A BALLOON-TIPPED CARDIOSCOPE

The right atrial posterior septum, including the coronary sinus (CS) o stium, is an important landmark in radiofrequency catheter ablation th erapy for supraventricular tachycardia or atrial flutter. The anatomic al findings around the CS ostium would be useful to determine a target site or line during catheter ablation. The aim of the study was to te st the ability of the imaging catheter to identify structures in the p osterior septal area of the right atrium and to evaluate the feasibili ty of guidance for catheter placement in the CS using a cardioscope th at we recently developed. In 12 anesthetized dogs, the cardioscope, co nsisting of a deflectable 7 Fr fiberoptic endoscope with an inflatable and transparent balloon, was introduced into the right atrium via the femoral vein. The cardioscope was manipulated to observe the right at rial posterior septum. A deflectable electrode catheter was inserted v ia the jugular vein and positioned in the CS under cardioscopic guidan ce. In 10 of 12 dogs, the right atrial posterior septum, including the CS ostium, and the tendon of Todaro could be anatomically identified by cardioscopy. It was possible to position an electrode catheter in t he CS in all 10 dogs under direct vision without fluoroscopy. But the CS ostium could not be detected in the remaining two dogs, although th e cardioscope was placed at as many sites as possible. No complication occurred. The balloon-tipped cardioscope appears to be useful in obse rving the right atrial posterior septum and in guiding an electrode ca theter into the CS.