[Study using the Noble model of excitation propagation through a branching node]

Excitation propagation through a branching node with 3 thin branches fused into a thick one has been studied on Noble model. When the ratio of the diameters of thin and thick branches equals 1 : 10 the propagation is blocked. When the diameter ratio is 1 : 8 and excitation comes asynchroneously (along one of input branches 10 msec later than along two others) a 30 msec delay of propagation is observed. The importance of the results obtained for explaining atrio-ventricular delay is discussed.