What is Diagnosis of Heart Disease in the Newborn ?
Clinical diagnosis of heart disease in the newborn can be quite challenging. Manifestations of potentially life threatening CHD are often subtle and can be confused with non-cardiac conditions.
The hyperoxia test: The hyperoxia test is frequently used to rule out critical CHD (conditions that are fatal without specific interventions in the newboil1 period). This test is based on the principle that administration of 100 per cent oxygen can raise the PO, of the arterial blood to a much higher level in absence of shunting from cardiac causes. It requires estimation of PO,.
The echocardiogram: When doubts persist whether a patient has CHD or not despite a thorough clinical exam and chest X-ray and ECG, an echocardiogram may be performed. This is especially true if the patients clinical condition does not permit adequate clinical evaluation. Such a situation is not infrequent in neonates.
The ECG and Chest X-ray: Beyond the neonatal period, a normal ECG and chest X-ray makes the diagnosis of a hemodynamically significant heart defect unlikely. In young infants, assessing heart disease is often difficult because of a large thymus. The radiographic assessment of pulmonary blood flow is difficult even for the experienced observer but it is even more difficult in an infant where the arteries and veins are small.