Electrocardiographical investigations of normal and malformed embryo and foetus hearts in humans, mammals, and avians. Electrocardiographical investigations of the experimentally malformed heart of the chick foetus.

The experimental technique was based on the injection of a 0.5 % Janus green B solution into the embryonic pharynx through a branchial slit, at the age of three days. This method of chemical endocauterization of the pharynx was elaborated by B. Menkes. Our experimental method produces a necrotizing intoxication of an extracardiac region (the region of the branchial arches) and cardiovascular malformations similar to those observed in human pathology have been obtained. This experimental group consisted of chick foetuses of 9 -- 11 days; their interventricular septation is normally fulfilled at the end of the 8th day of incubation. 342 foetuses with or without cardiovascular malformations have been examined by electrocardiography and 678 electrocardiographs have been recorded. Normal electrocardiographs of chick embryos were similar to those recorded in mammal and human embryos. The probability of a cardiovascular malformation could be assumed by direct electrocardiography in a proportion of 80 -- 85% while indirect electrocardiography could allow the diagnosis in a proportion of only 60 %. There are no pathognomonic electrocardiographs for a certain type of malformation, but the grouping of certain alteration of the electrical recording can suggest the existence of a cardiovascular malformation. Electrocardiographs recorded with experimentally malformed hearts recall the patterns of human foetal pathology.