Fibrosis of the conducting tissue in infancy.

The conducting tissue of the heart was studied in a group of 38 cases of the sudden infant death syndrome and in a control group of 28 children dying of known causes. A variable amount of fibrous tissue was found in the atrioventricular complex in almost every case. There was a statistically significant increase in fibrous tissue with age in both groups and there was also significantly more fibrosis in the sudden infant death group compared with the controls. Possible explanations for these findings are discussed and it is suggested that the results might be of aetiological significance in the sudden infant death syndrome.