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In this issue, a group from Oxford pathology and medical statistics present the 21st century detailed comparisons of adults' heart weights with other body statistics, as measured at autopsy. 1 Their results are markedly different from the standard tables that pathologists have been using through most of the last 100 years, which were derived from North America in 1928. 2 They also reinforce the need to include a comparative total body measurement (surface area and weight) when considering whether or not a heart is enlarged-a common question at autopsy-rather than just noting the heart weight and sex of the patient.
Using numerous statistical calculations on hearts and bodies of persons who died without obvious heart or lung disease, heart weight correlated best with body surface area and nearly as well with body weight. The calculus for body surface area is a complicated transformation of body weight and height, so pathologists will be grateful that body weight alone is satisfactory for most purposes. UK mortuaries increasingly measure height and weight of bodies-a recommendation that came from the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) 2006 report, where 45% of a large sample of coronial autopsy reports did not include a body weight. 3 That said, the calibration and consistency of many mortuary body and organ scales are, anecdotally, suboptimal.
A significant statistic from this study is that the normal heart/body weight ratio for both men and women, aged 14 years and above, who are not obese or malnourished, is 0.51%. According to the 1928 data, it is 0.43% and 0.4% for men and women, respectively. This historical difference may not seem much, but for a 70 kg female the difference between the 'normal' heart weight being 357 g vs 280 g; and for a 85 kg man, the difference being 434 g vs 366 g. This higher (0.51%) ratio is not actually new for our times: a normal ratio of 0.5% was published from Brazil, in 2002. 4
Why do we need tables and standards?
Case definitions matter for precision of investigating diseases and their epidemiology. In the area of sudden cardiac deaths when coronary atherosclerosis, hypertension and valvular disease are not the cause, several conditions have the exclusion of an enlarged heart...