One type of congenital heart defect is called atrial septal defect (ASD) where the left and right atria are not completely separated. ASD usually results in blood moving from the left atrium into the right atrium. This will cause increased blood pressure in the right atrium and decreased blood pressure in the left atrium. Which of the following rows describes the other effects of ASD on blood pressure and oxygenation?

Explanation

As the left atrium has oxygenated blood and the right has deoxygenated blood, as blood moves to the right atrium % oxygen will increase in the right atrium and so in the right ventricle and pulmonary artery as well (as that's the blood pathway). Since the right atrium has more blood and hence a higher blood pressure, more blood will enter the right ventricle and so the pulmonary artery as well, increasing pressure in both. The same would happen to the left side, as less blood is present in the left atrium, and less blood will enter the ventricle and the systemic aorta, decreasing the pressure in both, so option D is correct as it is the only option with the right combination.