Human Fœtal Ventricular Outputs

Abstract

IN a comprehensive study of the fœtal circulation in the lamb, G. S. Dawes, Joan C. Mott and J. G. Widdicombe¹ showed that in the fœtus the left ventricular output exceeded that of the right ventricle. In a study of the ventricles of the post-natal human heart², I showed, by observations of the weight of the ventricular mass and of its parts, that right ventricular atrophy is the normal event in the period immediately following birth, and that the weight ratio between right and left ventricles which is characteristic of adult hearts is normally found from the age of six months onwards. Additional unpublished observations on the thickness of the ventricular walls during the period of right ventricular atrophy suggest that in the human fœtus, as in the lamb, the output of the left ventricle exceeds that of the right. As experimental observations of the type performed on the fœtal lamb are unlikely to be made on a human fœtus, these observations may be of some interest.