Three-dimensional analysis of the intrinsic cardiac ganglia in a young dog

The intrinsic ganglia of the heart of a young dog were studied by computer graphic reconstruction to determine the accurate location. The heart was embedded in celloidin, and transverse sections were cut. Using every third 60 microns section, a series of 49 sections was mapped. Three-dimensional (3D) images were constructed by a personal computer. Numerous intrinsic ganglia, most of which were located in the epicardiun, were observed. The intrinsic ganglia were found in the base of the aorta and pulmonary vessels and from the base of the superior vena cava to the right atrium, i.e., the sinoatrial nodal region. Using the 3D reconstruction technique, the locations of the intrinsic ganglia could be accurately identified. Furthermore, it was demonstrated that these ganglia formed several groups which formed a continuity. This study suggested that it was necessary to consider the existence of the numerous intrinsic ganglia, when we studied the cardiac innervation.