tailieunhanh - The Gale Genetic Disorders of encyclopedia vol 1 - part 5

Khi tâm thất trái hoạt động nhiều hơn để bơm máu đi khắp cơ thể, nó sẽ trở thành mở rộng. Trong coarctation của động mạch chủ, động mạch chủ là chế hơn, làm giảm lưu lượng máu đến phần dưới của cơ thể và tăng huyết áp trong cơ thể phía trên. | rowed. As the left ventricle works harder to pump blood through the body it becomes enlarged. In coarctation of the aorta the aorta is constricted reducing the flow of blood to the lower part of the body and increasing blood pressure in the upper body. A bicuspid aortic valve has only two flaps instead of three which can lead to stenosis in adulthood. Subaortic stenosis is a narrowing of the left ventricle below the aortic valve which limits the flow of blood from the left ventricle. Septal defects When a baby is born with a hole in the septum the wall separating the right and left sides of the heart blood leaks from the left side of the heart to the right or from a higher pressure zone to a lower pressure zone. A major leakage can lead to enlargement of the heart and failing circulation. The most common types of septal defects are atrial septal defect an opening between the two upper heart chambers and ventricular septal defect an opening between the two lower heart chambers. Ventricular septal defect accounts for about 15 of all cases of congenital heart disease in the United States. Cyanotic defects Heart disorders that cause a decreased inadequate amount of oxygen in blood pumped to the body are called cyanotic defects. Cyanotic defects including truncus arteriosus total anomalous pulmonary venous return tetralogy of Fallot transposition of the great arteries and tricuspid atresia result in a blue discoloration of the skin due to low oxygen levels. About 10 of cases of congenital heart disease in the United States are tetralogy of Fallot which includes four defects. The major defects are a large hole between the ventricles that allows oxygenpoor blood to mix with oxygen-rich blood and narrowing at or beneath the pulmonary valve. The other defects are an overly muscular right ventricle and an aorta that lies over the ventricular hole. In transposition reversal of position of the great arteries the pulmonary artery and the aorta are reversed causing oxygen-rich .