EFFECTIVENESS OF SINGLE RECTANGULAR ELECTRICAL PULSES OF KNOWN DURATION AND STRENGTH IN EVOKING AURICULAR FIBRILLATION

Publisher Website
Google Scholar
Abstract
A study of the responses of the dog''s auricle to stimulus shocks of variable intensity and duration revealed that an auricular vulnerable period during which fibrillation can be induced by single rectilinear shocks is located within the relative refractory period. The duration of shocks as well as their intensity is an important factor in the creation of fibrillation. All durations between 0.1 and 13 msec. are capable of creating fibrillation, but the longer durations are more effective and act at lower intensities. Progressive increase of shock intensity at any instant within the vulnerable period produces first extrasystoles, then fibrillation and finally no response at all (a disappearance phenomenon). The disappearance phenomenon is thought to be due to the larger field effects of of very strong stimuli. It, like fibrillation, can be obtained only during the relative refractory period. An explanation of the cause of fibrillation and vulnerability as well as of the disappearance phenomenon is offered.