UNIDIRECTIONAL BLOCK IN HEART MUSCLE

Abstract

By means of asymmetric pressure applied to the middle of a ventricular strip from the turtle heart, it is possible, in the greater number of cases, to produce irreciprocal conduction in the direction desired. An impulse passing from normal to a narrow region of strongly compressed muscle may pass on to a less strongly compressed region and thence into normal muscle. If the process is set up at the opposite end of the strip, so that it must traverse the less before reaching the more strongly compressed region, it may fail to pass the region of compression. Under similar conditions, before irreciprocal conduction appears, the impulse will usually traverse the strip more rapidly in the direction from stronger to weaker compression than the opposite.