Retrospectroscope

In experimental ventricular fibrillation studies directed toward identifying the critical mass, two factors have largely been uncontrolled: 1) the intensity and duration of the train of pulses used to induce ventricular fibrillation and 2) the size and location of the electrodes. Prolongation of the train of stimuli used to induce ventricular fibrillation will also prolong stimulation of the sympathetic nerve fibers in the myocardium at the site of the stimulating electrodes, which will be less with locally applied, small-area electrodes. When large-area electrodes are applied to the heart or chest to induce ventricular fibrillation, more current is required and the current spreads to stimulate more sympathetic nerve fibers in the ventricles.