Exams and Tests

Even if the bluish color and other symptoms have resolved by the time the child reaches medical attention, the health care provider will immediately suspect a heart problem. Medical tests will focus on identifying the cause of the cyanosis.

• Lab tests: The red blood cell count and hemoglobin may be elevated as the body attempts to compensate for the lack of oxygen to the tissues.
  
  
• Electrocardiogram (ECG): This painless, quick test measures and records the electrical activity of the heart. Structural abnormalities of the heart usually produce abnormal recordings on ECG. In tetralogy of Fallot, right ventricular hypertrophy is almost always present.
  
  
• Chest x-ray imaging: This image may demonstrate the classic "boot-shaped heart." This occurs because the right ventricle is enlarged. It also may show an abnormal aorta.
  
  
• Echocardiography: This imaging test is key. It will demonstrate the ventricular septal defect or large hole between the left and right ventricles, the degree of pulmonary stenosis, and it will reveal other unanticipated defects. Many patients do not need cardiac catheterization if the clinical, ECG, and echocardiogram findings are routine and as expected.
  
  
• Cardiac catheterization: This is an invasive procedure accomplished by a cardiologist in a special laboratory with the patient under local anesthesia. This procedure was done on all patients with suspected tetralogy prior to echocardiography, since it was the only procedure that could be used to confirm the diagnosis. If needed, a small tube (catheter) is inserted through the skin into a blood vessel (usually in the groin) and advanced up the inferior vena cava into the heart. An x-ray image is taken while a small amount of dye is infused. The dye helps highlight the ventricular septal defect, pulmonary stenosis, overriding aorta, and the size of the pulmonary arteries.