During the last ten years, the more general use of the electrocardiograph and the intensive study of cardiac conditions in children have revealed disturbances of rhythm and conduction in a considerable number of patients.
Heart block is one of the less common forms of abnormal cardiac mechanisms found in childhood. In 1922 I was able to collect thirty-six cases of heart block in infancy and childhood from the literature, and added one observed in a girl, aged 11 years, with a congenital cardiac lesion.1 The etiologic factors in the cases described were as follows: Diphtheria, sixteen cases; rheumatism, two cases; congenital syphilis, one case; cardiac tumor, one case; nose and throat infection, one case; associated congenital cardiac lesion, twelve cases and unknown cause, three cases.
Heart block occurring in patients during the course of diphtheria present the gravest outlook, the mortality in the collected cases having been 93.7 per