Vector velocity imaging echocardiography to study the effects of submassive pulmonary embolism on the right atrium.

Objectives: To assess the effects of submassive pulmonary embolism (SMPE) on right atrial (RA) anatomy and function.

Background: Right ventricular dysfunction (RVD) is associated with adverse outcomes in SMPE. However, the effects of SMPE on the structure and function of the RA have received much less attention.

Methods: Fifty patients with SMPE documented by CT angiography (SMPE group) and evidence of RVD on two-dimensional echocardiography were retrospectively identified and compared to 50 controls (control group). Both RA and RV areas, volumes and fractional area change (FAC) were measured. Pulmonary artery systolic pressures were estimated. RA and RV longitudinal strains were obtained using vector velocity imaging (VVI).

Results: Compared with controls, RA and RV FACs were significantly reduced and associated with higher chamber volumes in the SMPE group. Global longitudinal RA strain was reduced in the SMPE group (29% + 11% vs 55% + 16%; P < .01), as was global RV longitudinal strain (-12% + 5% vs -20% + 5%, P < .01), when compared to the controls. A linear relationship existed between RV and RA strain in both groups; however, the curve was shifted downward among those with SMPE. Furthermore, ROC curve analysis suggests RA area performs better than RV area as a marker of SMPE.

Conclusions: RA structure and function are adversely affected in SMPE, similar to the effects observed in RV. Lower RA strain appears to be a novel quantitative indicator of SMPE, and RA area may be a more sensitive marker of this condition and may provide additional prognostic information in this condition.