Which of the following disorders leads to cyanosis and tachycardia caused by complete mixing of deoxygenated and oxygenated blood in the left side of the heart resulting in systemic desaturation and variable pulmonary obstruction?


•Tricuspid atresia occurs when the tricuspid valve fails to develop. Without the tricuspid valve, there is no communication between the right atrium and the right ventricle.

•Tricuspid atresia allows no blood to flow from the right atrium to the right ventricle. Instead, blood crosses through an atrial septal defect, into the left atrium, bypassing the lungs and the step of oxygenation.

•Blood reaches the lungs for oxygenation by being shunted back through a ventricular septal defect into the pulmonary artery.

•These structural abnormalities result in deoxygenated blood in the systemic circulation, causing cyanosis and tachycardia.

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