RV enlargement may be caused by states of acute or chronic pressure overload, chronic volume overload, or intrinsic myocardial pathology, often indicating severe and/or advanced disease with a relatively poor prognosis. The infant RV has limited capability to adapt to different loading conditions associated with pneumonia and acute respiratory failure as compared to adults. The accurate assessment of RV size and functions is important in the management, and prognostication of these conditions. A reliable echocardiographic evaluation of the RV systolic and diastolic dysfunction is challenging owing to its complex morphology, and different physiology compared to the left ventricle. This review provides an approach to assessing a combination of different parameters of RV function and pulmonary hypertension in children with pneumonia and respiratory failure. The area of the body and apex of the RV is measured by planimetry of the RV cavity in the apical four-chamber view at end-diastole (when the RV cavity is at its largest)