Nghiên cứu này có thể được bình thường, nhưng thông thường nó cho thấy một cái bóng trên rất hẹp trung thất ("trứng trên một thanh" xuất hiện). c. Điện tâm đồ (ECG). Có không có kết quả điện tâm đồ đặc trưng. d. Siêu âm tim là chẩn đoán. Phát hiện điển hình bao gồm phân nhánh | 1. D-transposition of the great arteries is the most common cardiac cause of cyanosis in the first year of life with a male-female ratio of 2 1. The aorta comes from the right ventricle and the pulmonary artery from the left ventricle with resultant separate systemic and pulmonary circuits. With modern newborn care the 1-year survival rate approaches 80 . a. Physical examination. Typical presentation is a large vigorous infant with cyanosis but little or no respiratory distress. There may be no murmur or a soft systolic ejection murmur. b. Chest x-ray study. This study may be normal but typically it reveals a very narrow upper mediastinal shadow egg on a stick appearance . c. Electrocardiography ECG . There are no characteristic ECG findings. d. Echocardiography is diagnostic. Typical findings include branching of the anterior great vessel into the innominate subclavian and carotid vessels and branching of the posterior great vessel into the right and left pulmonary arteries. e. Cardiac catheterization. Like echocardiography this study is diagnostic and often therapeutic as outlined next in Congenital Heart Disease section II F 1 f. f. Treatment. If severe hypoxia or acidosis occurs urgent balloon atrial septostomy can be done under echocardiogram guidance in the nursery. Cardiac catheterization with balloon septostomy and subsequent arterial switch operation are methods of treatment. 2. Tetralogy of Fallot. Tetralogy of Fallot is characterized by four anomalies pulmonary stenosis ventricular septal defect overriding aorta and right ventricular hypertrophy RVH . There is a slight male predominance. Cyanosis usually signifies complete or partial atresia of the right ventricular overflow tract or extremely severe pulmonary stenosis with hypoplastic pulmonary arteries. The degree of right ventricular outflow obstruction is inversely proportional to pulmonary blood flow and directly proportional to the degree of cyanosis. Tetralogy of Fallot with absent pulmonary valve
