1. An autopsy case of fatal arrhythmia induced by injuries of the atrioventricular conduction system: A case report

A 65-year-old woman died three days after being involved in a traffic accident, following an episode of ventricular fibrillation. She was diagnosed as having suffered cardiac contusion, liver contusion, mediastinal hematoma and rib fracture on admission. Her electrocardiogram showed complete right bundle branch block, complete atrioventricular block, and right axis deviation. Aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and creatine kinase-MB were found to be elevated on biochemical blood analysis. These findings recovered and her condition appeared to improve daily. At autopsy, epicardial and intramyocardial haemorrhage were macroscopically seen in the posterior wall of the bilateral ventricles. On microscopic examination, there was evidence of fresh haemorrhage and coagulative necrosis with inflammatory reaction in the ordinary myocardium and adipose tissue around the atrioventricular node, which had spread to the proximal portion of the His' bundle. It is considered that these findings caused ventricular fibrillation to occur, and that the cause of death in this case was myocardial contusion due to blunt thoracic injury. This case would indicate that myocardium nearby atrioventricular junction is vulnerable to external force. Moreover, it would seem that fatal arrhythmia occasionally occurs during the follow-up stage, despite the lack of any significant clinical findings.