Slide show: Common types of congenital heart defects
Image of heart with truncus arteriosus
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This is a defect in which the normally separate pulmonary artery and aorta merge into one single large vessel (truncus) arising from the two bottom chambers of the heart (right and left ventricles). Many people who have this defect also have a large ventricular septal defect, which turns the right and left ventricles into a single chamber. This allows red oxygenated blood and blue unoxygenated blood to mix. Too much blood may flow to the lungs, flooding them and making it difficult to breathe. It can also result in life-threatening pulmonary hypertension — high blood pressure in the lungs.

Surgery is needed to close the septal defect with a patch and to separate the pulmonary arteries from the trunk.

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