THE QUESTION OF CARDIAC HYPERTROPHY DURING PREGNANCY

Abstract

The heart wt. (HW/BW) ratios were detd. in the following manner: Animals which had been kept on a standard diet for several days were weighed and then killed by a blow on the head. The heart was removed from the pericardial sac, and the great vessels trimmed flush with the surface. The cardiac chambers were cut open and washed free of blood. The excess moisture was removed by blotting the organ with filter paper, and the organ weighed carefully. The ratio was detd. by dividing the heart wt. in g. by the body wt. in kilog. The normal HW/BW ratio in 90 normal adult $ guinea pigs was found to be 3.17 g. per kilo. 26 animals were killed within 72 hrs. after parturition. The average HW/BW ratio was found to be 3.06 g. per kilo. 26 animals were killed after pregnancy had progressed for about 7 wks. The average HW/BW ratio was found to be 2.93 g. per kilo. After the wt. of the uterine contents had been subtracted from the body wt. the ratio in these animals was 3.17 g. per kilo; identical with the normal figure. Corroborative data were also obtained from 10 cats and 7 dogs. Since it was found that pregnancy did not influence HW/BW ratio in the lower animals it seems doubtful that pregnancy would produce cardiac hypertrophy in the human. The work further shows that increased cardiac work does not necessarily produce cardiac hypertrophy.