Role of the nervous system in the arrhythmias produced by coronary occlusion in the cat

Abstract

The importance of the nervous system in the arrhythmias generated by occlusion of the left coronary artery of the cat was investigated. This was carried out by (1) monitoring the spontaneous electrical activity in sympathetic and parasympathetic cardiac nerves and (2) determining the influence of ablation of the nervous system on time taken for death to occur and on incidence of ventricular fibrillation. It was found that coronary occlusion increased the spontaneous firing in cardiac-bound autonomic fibers and that the enhanced neural activity was correlated in time with electrocardiographic changes consisting of ventricular arrhythmias. Removal of the central nervous system and both vagi conferred protection against arrhythmogenesis. Animals with no neural input to the heart (as indicated by the nerve recordings) survived more than twice as long after coronary occlusion and showed a significant reduction in the incidence of ventricular fibrillation. These results suggest that the nervous system plays an important role in the generation of arrhythmias produced by coronary occlusion in the cat.