Abstract
The role of the central nervous system (CNS) in arrhythmogenesis in the 4 h period following occlusion of a coronary artery was investigated in rats by use of CNS ablations and other procedures. Ablations in the CNS included pithing, spinalization and decerebration combined with acute and chronic surgical preparation and noradrenaline/adrenaline infusions. All procedures involving acute surgery reduced the incidence and severity of the arrhythmias induced by occlusion. Such reductions were most marked in the second (0.5-4 h post-occlusion) arrhythmic period. The observed reductions in arrhythmias could not be explained in terms of involvement of the CNS or adrenoceptor activation. When circulating leucocytes, platelets and serum potassium were measured in a group of pithed rats before and after occlusion, reduced levels (20-50%) of both leucocytes and platelets occurred while serum potassium levels rose by 50-100%. Arrhythmias following coronary occlusion may depend in part on factors in the blood such as leucocytes, platelets and serum potassium and these factors may be altered by acute surgery.