Study limitations:
Our study aims to provide a general picture of RV dysfunction assessments by different echocardiographic parameters in different diseases, so a disease-specific analysis was not performed. Statistically, the ROC analysis showing the accuracy gives a satisfactory correlation. However, the inherent limitations of measurement of variables exist. The study did not use three-dimensional echocardiography, and the right ventricle’s unique geometry makes it difficult to obtain images using two-dimensional planes. RVEF is a function of both longitudinal and concentric myocardial fibers, while tricuspid annular systolic motion principally indicates the longitudinal fibers’ function only. The angle of interrogation and cardiac motion influence the velocity measurement, especially from the apical four-chamber view during long axis assessment limiting the accuracy of S’. As mentioned above, RVEF measured by MRI can account for some unknown extent of variability of data. Lack of 3D echocardiographic assessment of RV function in our dataset remains a limitation in our study. Prior studies have shown a good correlation 3D TTE with MRI for the assessment of RV function. Good 3D assessment of RV function requires excellent image quality, lack of arrhythmia and long breath holds during image acquisition. It is prone to stich artifacts, needs cumbersome software processing, has low frame rate and significant inter-vendor variability, hampering routine use of 3D RV assessment in contemporary practice.