Electrocardiogram In the absence of conditions for cardiac ultrasound, the electrocardiogram may suggest certain characteristic changes of heart disease, such as severe leftward deviation of the electrical axis suggesting endocardial cushion defect; leftward deviation of the electrical axis with left ventricular hypertrophy suggesting tricuspid atresia, or right ventricular dysplasia and pulmonary atresia. Chest radiographs A chest radiograph may be obtained if heart disease is suspected in the newborn. Usually, an egg-shaped heart suggests transposition of the great arteries and a boot-shaped heart suggests tetralogy of Fallot. Echocardiography This includes M-mode ultrasound, 2D ultrasound, Doppler ultrasound and, in recent years, 3D ultrasound, which is the most valuable diagnostic method for heart disease in the neonatal period. For newborns, it can diagnose all kinds of cardiac, macrovascular and coronary artery malformations, and determine cardiac function and pulmonary artery pressure because of the clear images displayed. And. This test is non-invasive and easily accepted by parents and children, and can be used to dynamically observe changes in the heart. Cardiac magnetic resonance imaging This is also a non-invasive test, mainly used for malformations of the heart that cannot be diagnosed by echocardiography, such as peripheral pulmonary artery malformations and visceral ectopia. Cardiac catheterization and cardiovascular angiography With the development of echocardiography, the diagnostic value of cardiac catheterization has taken a back seat and is mainly used for arteriovenous bypass and distal pulmonary artery dysplasia that cannot be seen by echocardiography. However, for complex cardiac malformations, cardiac catheterization and cardiovascular angiography are required before surgery to further define the cardiac malformations and various physiological indicators. Currently, cardiac catheterization and cardiovascular angiography are more commonly used for therapeutic purposes, such as early neonatal atrial septal fistula and arterial catheter occlusion.