[Role of the atrium in the functional organization of the sinoatrial node]

The automatic activity of the venous sinus was studied in respect to the atrial bioelectrical activity in frogs. Each of the two parts of the divided venous sinus had different rhythms. Extra-cellular recording revealed that the APs of both parts of the sinus were closely synchronized if the parts were connected with the atrium. The data obtained suggests that this synchronization was due to atrial bioelectrical activity.