Normally, the lungs are examined first, then the heart is examined if there are no apparent problems with the lungs. These examinations are typically performed using ultrasound, known as an echocardiogram when performed on the heart. Chest x-rays and electrocardiograms may also be used in reaching or confirming a diagnosis; however, an x-ray may appear normal immediately following birth. If d-TGA is accompanied by both a VSD and pulmonary stenosis, a systolic murmur will be present.On the rare occasion (when there is a large VSD with no significant left ventricular outflow tract obstruction), initial symptoms may go unnoticed, resulting in the infant being discharged without treatment in the event of a hospital or birthing center birth, or a delay in bringing the infant for diagnosis in the event of a home birth. On these occasions, a layperson is likely not to recognize symptoms until the infant is experiencing moderate to serious congestive heart failure (CHF) as a result of the heart working harder in a futile attempt to increase oxygen flow to the body; this overworking of the heart muscle eventually leads to hypertrophy and may result in cardiac arrest if left untreated. Description
In a normal heart, oxygen-depleted ("blue") blood is pumped from the right side of the heart, through the pulmonary artery, to the lungs where it is oxygenated.
The oxygen-rich ("red") blood then returns to the left heart, via the pulmonary veins, and is pumped through the aorta to the rest of the body, including the heart muscle itself.With d-TGA, deoxygenated blood from the right heart is pumped immediately through the aorta and circulated to the body and the heart itself, bypassing the lungs altogether, while the left heart pumps oxygenated blood continuously back into the lungs through the pulmonary artery. In effect, two separate "circular" (parallel) circulatory systems are created, rather than the "figure 8" (in series) circulation of a normal cardio-pulmonary system. Variations and similar defects
Arterial spatial relationships
Differences in the shape of the atrial septum and/or ventricular outflow tracts affect the relative positions of the aorta and pulmonary artery. In the majority of d-TGA cases, the aorta is anterior and to the right of the pulmonary artery, but it can also be directly anterior or anterior and to the left. The aorta and pulmonary artery can also be side by side, with aorta on either side. This is a less common variant, and with this arrangement, an unusual coronary artery pattern is common. There are also some cases with aorta to the right and posterior to the pulmonary artery. Simple and complex d-TGA
d-TGA is often accompanied by other heart defects, the most common type being intracardiac shunts such as atrial septal defect (ASD) including patent foramen ovale (PFO), ventricular septal defect (VSD), and patent ductus arteriosus (PDA). Stenosis of valves or vessels may also be present.