Weights of Cardiac Ventricles at and After Birth

the right as being less; and Patten (1930) found that the right outweighed the left by 8:7. There is also a difference of opinion regarding right ventricular weights after birth. Muller (1883) demonstrated a post-natal physiological "atrophy". Brock (1932) considered that there was normal weight gain, and lately Keen (1955) has again found a post-natal "atrophy", maximal at two months. We have recently demonstrated (Macdonald and Emery, 1960) that the foetus up to the age of approximately 30 weeks has a heart with left ventricular preponderance. This is reversed in later intrauterine life, but apparently again begins to revert towards left ventricular preponderance during the last few weeks before full term. The present study is an attempt to determine the weights of the right and left ventricles of the normal full-term infant following birth and during infancy. MATERIAL AND METHODS Over a thousand hearts from live-born children of all ages were available for study. These hearts came from necropsies carried out by the Department of Pathology at the Children's Hospital, Sheffield. From this material a careful selection was made, eliminating all cases in which there