What is complete transposition of the great arteries?

summary

Complete transposition of the great arteries refers to the transposition of the aorta and the pulmonary artery. The aortic valve is not in the right posterior of the pulmonary valve, but in the right anterior, connecting with the right ventricle; The pulmonary valve is behind the left aortic valve and connected to the left ventricle. Transposition of the great arteries is the most common cyanotic congenital heart disease in the newborn period, with an incidence rate of 0.2 to 0.3 per thousand. The ratio of male to female is 2-4:1.

What is complete transposition of the great arteries?

Transposition of the great arteries is the most common cyanotic congenital heart disease in the newborn period, with an incidence rate of 0.2 to 0.3 per thousand. The ratio of male to female is 2-4:1. The incidence rate of the mother with diabetes is 11.4 times higher than that of the normal mother. The incidence rate of pregnant women who use hormone and anticonvulsant drugs is higher in the early pregnancy. If not treated, about 90% of the patients will die within 1 years of age.

Under normal conditions, the inferior conus of the pulmonary valve developed, and the pulmonary artery was located in the left anterior superior; The subvalvular conus is atrophic and the aorta is located at the right posterior inferior. During transposition of the great artery, the subvalvular conus of the aorta was developed and not absorbed, and the aorta was located at the upper right anterior; The pulmonary artery was located in the left posterior inferior part. In this way, the pulmonary artery connects to the left ventricle backward and the aorta to the right ventricle; There was a muscular connection between the aortic valve and tricuspid valve due to the existence of conus; There was no conus under the pulmonary valve, and there was a fibrous connection with the mitral valve. The common complications are: atrial septal defect or patent foramen ovale, ventricular septal defect, patent ductus arteriosus, pulmonary artery stenosis, etc.

If complete transposition of the great arteries is not accompanied by other malformations, two parallel loops are formed. The venous blood from superior vena cava and inferior vena cava is supplied to the whole body through the transposed aorta of right heart, while the oxygenated blood from pulmonary vein is injected to the lung through the transposed pulmonary artery of left heart. Patients must rely on intracardiac communication (patent foramen ovale, atrial septal defect, ventricular septal defect) or extracardiac communication (patent ductus arteriosus, collateral vessels) for blood flow mixing. The hemodynamic changes of this disease depend on whether it is associated with other malformations, the degree of communication and mixing of left and right cardiac blood and whether the pulmonary artery is narrow.

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In the early stage, clubbing fingers and toes appeared. After birth, the heart may not have obvious murmur, but there is a single loud second heart sound, which comes from the aortic valve closing sound near the chest wall. If it is accompanied by large ventricular septal defect or large arterial duct or pulmonary artery stenosis, the murmur produced by the corresponding malformation can be heard. In the case of patent ductus arteriosus, continuous murmur can be heard in the second intercostal space on the left edge of sternum; in the case of ventricular septal defect, systolic murmur can be heard in the third and fourth intercostal space on the left edge of sternum; in the case of pulmonary artery stenosis, systolic ejection murmurmur can be heard in the upper edge of the left edge of sternum. When the noise is loud, it is often accompanied by tremor. Generally, patients with large ventricular septal defect have early heart failure and pulmonary hypertension, but patients with pulmonary stenosis have obvious cyanosis, and heart failure is rare.