Pathologic changes in the cardiac conduction and nervous system in sudden coronary death

The arrhythmogenic substrates for sudden coronary death were studied in 13 autopsied hearts and in 2 left stellate ganglia (surgically excised). Diffuse or segmentary obstruction of nutritional arteries accounted for acute ischemic injury of the conduction system, which was the underlying cause of high-risk bradycardic arrhythmias in one-third of the cases. However, in one-quarter of the cases the survival of anoxia-resistant subendocardial specialized fibers was probably responsible for reentrant lethal tachycardic arrhythmias. In other cases, early infarct damage could have fatal arrhythmias of either type. Intrinsic and/or extrinsic neuropathologic changes, unbalancing the autonomic action on the heart, were often seen to participate in the arrhythmogenic features of sudden coronary death.