This is the largest series showing the significant value of reduced LA volume for predicting mortality among patients with PE and the only existing quantitative report on diagnostic CTPA scanning in this setting. Its main novelty is the concept of assessing LA volume rather than the traditionally used right ventricular dimensions for risk stratification in acute PE. Our cohort is composed mainly of whites; thus, the effect of race on chamber size is probably not significant. Because of the retrospective nature of this work, the measured cardiac volumes could not be adjusted for weight or body surface area (BSA). Moreover, routine CTPA is not cardiac-gated; thus, there is currently no validated way for adjusting the volumes to those parameters. However, the right to left atrial volume ratio was also associated with mortality, and it had a relatively similar discrimination ability. Since both atria are located in close proximity, they were scanned at approximately the same phase of the cardiac cycle, leading to a lesser effect of the phase variable and the patient’s BSA.