[Mechanism of spiral waves initiation in active media, connected with critical curvature phenomenon].

While studying on a digital computer a dimeric active medium described by Fitz-Hew, Nagumo equations a new mechanism of spiral waves initiation was observed. It has been shown that when the wave rounds the barrier where Neuman baundary conditions are set (dE/dn = 0) the wave separates from the border and the breakage of the front takes place; then it develops into a spiral. The effect is observed when the curvature of breakage is close to the critical one for the given medium. The results obtained may be of interest for explaining the mechanism of initiation of spiral waves in the damaged regions of the myocardium tissues.