Pediatric Heart Defects: Diagnostic Procedures

Such a wide variety of cardiac abnormalities make proper diagnosis a specialized skill requiring sophisticated testing and skilled interpretation of diagnostic information with a high degree of certainty.

Can heart defects be diagnosed before a baby is born?
Yes. Structural heart defects can be detected in an unborn child using fetal echocardiography (ECHO). An echocardiogram is a graphic outline of the heart's movement created from ultrasound vibrations (high frequency sound waves) echoed from the heart's structures. A wand or transducer is placed on the mother's abdomen so the doctor can see the outline of the movement of the baby's heart.

While not all cardiac abnormalities can be detected prenatally, most defects can be identified this way. A fetal ECHO is a safe procedure that produces no side effects. An ECHO usually is performed no sooner than after the eighteenth week of pregnancy, but images may obtained earlier, under certain circumstances. Ideally, the procedure should be performed between 20 and 22 weeks.

What indicators might suggest a potential fetal heart abnormality?
Certain key factors may indicate a potential fetal heart abnormality. Factors that suggest the need for echocardiography or other testing include:

• Abnormalities found during routine obstetric ultrasound
• A pregnant mother who has previously given birth to a child with a congenital heart defect
• A pregnant mother who has diabetes
• The presence of other fetal birth defects
• An abnormal fetal heart rhythm

Can heart abnormalities be treated before the baby is born?
Yes, but the treatment and outlook for each developing baby depends on the heart abnormality and its severity. In some cases, no treatment is necessary and life expectancy is normal. If treatment is required to correct fetal arrhythmia (irregular heartbeat), it may come in the form of medication administered to the mother or directly to the fetus.

Currently, there are no intrauterine (within the uterus) surgical treatments. However, identifying defects before a baby's birth allows for more careful follow-up care during the remainder of the pregnancy as well as after birth. The mother also can be referred to a specialized care facility for delivery of the baby and/or medical and surgical care after the child's birth.

What indicators might suggest a potential heart abnormality in a newborn?
General observation of a newborn may provide evidence of a potential heart abnormality. Some basic signs may include:

• Overall discoloration: An O2 (oxygen) saturation test is a non-invasive procedure to determine the concentration of oxygen in the blood; low oxygen levels may suggest a heart or lung problem
• Careful examination of breathing patterns may indicate a need for a chest X-ray or further examination of the heart
• Evidence of a heart murmur (see the description below)
• Abnormal blood pressure

What indicators might suggest a potential heart abnormality in an infant or child?
General observation of an infant or older child may provide evidence of a potential heart abnormality. Some basic signs may include:

• A heart murmur
• Syncope (fainting spells)
• Heart palpitations (forcible or irregular pulsation)
• Poor weight gain
• Rarely chest pain or low tolerance for exercise

What is a heart murmur?
All children have heart murmurs. Normal sounds of vibration or flow within the heart can be heard during routine examination and these normal sounds are called "innocent" heart murmurs. Innocent murmurs are harmless and may disappear and reappear from one examination to the next. In most cases, the family physician or pediatrician can determine which sounds are innocent murmurs and which require further evaluation.

A pediatric cardiologist can evaluate an unusual or suspicious murmur and determine if further testing is needed. If your child has an innocent murmur, he or she does not have to limit his or her activity, take antibiotics before dental work or follow any other special precautions.

If a heart defect is suspected, what further testing is required to diagnose an abnormality in an infant?

• Echocardiography is the standard testing for diagnosing heart abnormalities. The procedure should be performed in a facility with physicians who have extensive experience in imaging children and diagnosing congenital heart disease, preferably an accredited laboratory.
• An electrocardiogram (ECG) can detect abnormalities in heart rhythm.
• A Holter monitor or event recorder can monitor and record information about the heart's rhythm over a period of 24 hours for further diagnosis.

What testing should be performed for older children or adolescents?
An older child suspected of having a potential heart defect should have a thorough physical exam performed, particularly prior to participating in competitive sports. The examination should include:

• A thorough review of the family's medical history
• A complete medical history
• A careful physical examination
• Ausculation: listening with a stethoscope to the sounds made by the heart; this should be performed both standing and lying down
• Blood pressure reading

Magnetic Resonance Imaging and Cardiac Catheterization
Magnetic resonance imaging (MRI) is a test that produces very clear pictures, or images, of the human body without the use of X-rays. MRI uses a large magnet, radio waves and a computer to produce these images.

Cardiac catheterization is a procedure in which a long, slender tube -- called a catheter -- is inserted through a blood vessel in the groin or arm and guided into the heart.

Both MRI and cardiac catheterization are used to answer specific diagnostic questions which cannot be answered using less invasive methods.

In general, the approach to diagnosis of heart abnormalities should be individualized and follow a natural progression of testing through which diagnostic information is used to determine the need for further testing. One child may need only a careful medical history and thorough physical examination, whereas another may need extensive testing to fully identify and understand the problem.

Summary