Histology slide is non-repeatable, non-reproducible and unreliable in estimating post-mortem heart wall thickness

A routine measurement in heart examination is that of the heart wall thickness. This study investigated whether histology can be used to estimate heart wall thickness measured in a post-mortem examination, and therefore assess the utility of this method in the post-mortem report peer review process. This study compared 30 consecutive adult heart measurements (left and right free wall thickness and interventricular wall thickness). It showed that heart wall thickness measurements on histology slides were non-repeatable, non-reproducible, and unreliable, with overall poor to moderate intraclass correlation coefficient (<0.60, p < 0.05). The 95% confidence interval in the difference between histology and post-mortem examination was 1-3.5 mm for left ventricle and interventricular wall thickness, and -1-0.5 mm for the right ventricle. This study showed limited utility in using histology in estimating heart wall thickness. However, in instances where histology was the only modality available to estimate heart wall, marking where the measurements were taken, citing the confidence intervals, and noting the limitations thereof is recommended.