Development of an endocardioscope for repair of an atrial septal defect inthe beating heart

The purpose of this study was to evaluate the possibility of surgical treat ment of an atrial septal defect in the beating heart without cardiopulmonar y bypass. The first step was to develop an endocardioscope that permitted o bservation of the inside of the beating heart. To visualize the inside of t he beating heart, the tip of the endoscope was covered with a glass adapter . The endocardioscope was inserted through the right atrial appendage in ei ght beagles. The atrial septum, foramen ovale, coronary sinus, tricuspid va lve, and chordae tendineae were identified without hemodynamic derangement. The second step was to attempt to close the foramen ovale with clips or st aplers. We were able to close the foramen ovale with these devices, but a s afer, easier device is needed. The endocardioscope we developed should prov e to be a useful tool for minimally invasive surgical treatment of heart di seases, such as atrial septal defect.