Estimation of Postcardiac Arrest Interval Based on Atrial Cavity Density in Postmortem Computed Tomography

Background: Intracardiac hypostasis is frequently observed in postmortem computed tomography (PMCT) of acute deaths, and it becomes clearer as the postmortem interval increases. To determine the postcardiac arrest interval (PCAI), we evaluated densities of the right and left atria [anterior part of the right atrium (AR) and posterior part of the left atrium (PL)] using postmortem computed tomographic images. Methods: A total of 184 patients were included in the study. Patients with return of spontaneous circulation and those with final alive confirmation time over 1 hour were excluded. We evaluated the density of AR and PL at the level of the right inferior pulmonary vein entry to the left atrium. We defined the interval between the estimated cardiac arrest time and the postmortem CT time as the PCAI. Results: There was a negative correlation between AR and PCAI in 59 patients who died owing to cardiovascular disease. The regression equation (PCAI = −1.725 × AR + 132.95) was obtained based on this result. There was no correlation between PL and PCAI. Conclusion: The result suggests that the density of the anterior part of the right atrium decreases as postcardiac arrest interval increases in the case of cardiovascular disease. The regression equation may be used as an additional method to estimate postcardiac arrest interval.