His bundle haemorrhage and external cardiac massage: histopathological findings.

Histological examination showed acute haemorrhage of the bifurcating His bundle and of the left bundle branch in a 35 year old man who died after being given external cardiac massage for cardiac arrest. "Hammering" of the ventricular septum crest against the central fibrous skeleton of the heart by compression of the sternum was believed to have caused the haematoma of the junctional tissue.