The heart in this defect has four chambers but only three valves. The big vessel is called a truncus.
Blood goes from the truncus both to the body and to the lung arteries.
Surgery can be performed to close the hole and separate the blood flow going to the lungs and the body. Truncus arteriosus sometimes happens in children with genetic disease or abnormal chromosomes. Pulmonary arteries arise from aorta Truncal valve, occasionally quadracuspid, stenotic and or insufficient.