Final answer:
Post-stenotic dilatation of the main pulmonary artery is a two-dimensional echocardiographic finding associated with valvular pulmonic stenosis.
Step-by-step explanation:
Post-stenotic dilatation of the main pulmonary artery is a two-dimensional echocardiographic finding that is associated with valvular pulmonic stenosis. Valvular pulmonic stenosis is a condition in which the pulmonic valve becomes narrowed or obstructed, causing blood flow from the right ventricle to the pulmonary artery to be restricted. As a result, pressure builds up before the stenotic valve, causing the dilation of the main pulmonary artery.