Comparing fist size to heart size is not a viable technique to assess cardiomegaly

Several medical textbooks state that a human heart is approximately the size of that person's fist. Stating that a heart has the size of the corpse's fist is thought to signify that the heart size is normal. We formulate two hypotheses that are tested in this article. First, we hypothesize that in cases without cardiomegaly, volumes of the hand and the heart are not significantly different. Second, we hypothesize that in cases of cardiomegaly, the heart volume statistically significantly exceeds that of the hand.

We retrospectively reviewed 130 consecutive postmortem computed tomography datasets from the BLINDED starting from 01/01/2013, covering a period of approximately 3 months. Hands and hearts were segmented and their volumes estimated. We obtained the following information from the postmortem examination reports: age, sex, body length and weight, heart weight, cardiomegaly, and cause of death.

When exploring the correlation between mean hand volume and heart volume, only in the group of the females with cardiomegaly (N=8) could a positive, statistically significant correlation be ascertained (Pearson correlation coefficient 0.753, P=.031).

In this study, we demonstrated that the commonly used idea that a heart larger than the fist of a patient suggests cardiomegaly might be incorrect. Because this perception is commonly used in autopsy reports, it might lead to avoidable errors. Until further studies confirm this hypothesis, this informal measurement should no longer be taught or used.