PDAThe pressure in the aorta is higher than that of the pulmonary artery during both systole and diastole. Therefore, in PDA blood shunting will occur from left to right during both systole and diastole.

The pulmonary arteries will dilate due to the increased pulmonary blood flow (arrows indicate dilated main pulmonary artery). There will also be prominant pulmonary vascular markings

The left atrium will also dilate.