Limitations
Our sample size was limited by the number of patients with complete hemodynamic data and with good quality echocardiographic images for the measurement of RA/LA volumes. Although 2D Echo is widely available and considered a useful tool for the measurement of the atrial dimensions and function, it is however limited by the absence of an orthogonal plane and reliance on geometric assumptions of atrial chambers [19]. For these reasons, 3D Echo is considered to be superior to 2D Echo [20]. Acquisition of quality 2D echo is limited in the setting of ventilation, obesity, pulmonary edema, and the limited ability to position patients with cardiogenic shock. Although the echo images were not obtained simultaneously with the hemodynamic measurements, changes in atrial size happen over time due to atrial remodeling in the setting of volume or pressure overload.