Once the lesion is suspected, an electrocardiogram and
chest radiograph should be performed. The electrocardiogram
will demonstrate right axis deviation and prominent
right ventricular forces, with large R waves in the anterior
precordial leads and large S waves in the lateral precordial
leads [19]. Although the electrocardiogram is similar to
that of a normal newborn, the right ventricular hypertrophy
and right axis deviation will not normalize in a
patient with tetralogy of Fallot. The classical chest radiograph
will demonstrate a boot-shaped cardiac silhouette.
This is due to upward displacement of the right ventricular
apex as a consequence of the right ventricular hypertrophy,
and a narrowing of the mediastinal shadow due to
the hypoplastic pulmonary outflow tract.