[Impulse propagation in an active unidimensional medium with a trigger-type region of nonuniformity]

Effects are considered which appear during impulse propagation along the active line, some elements of which are converted from the expecting regime to the trigger one. At the set length of the non-uniformity the critical value of the parameter exists, up to which the propagating impulse "takes no notice" of the trigger region. When the parameter values are higher than the critical value, the trigger region starts to generate the propagating impulses. In pathological working regimes of biological excitable media such non-uniformity may induce fibrillation.