Heart Disease - Diagnosing Congenital Heart Defects

The majority of heart defects obstruct the flow of blood flow in the heart or nearby vessels, cause abnormal blood flow patterns, or result from the incomplete formation of the heart. Symptoms vary depending on the defect. Cyanosis, the bluish appearance of the skin, lips and fingernails, signals a number of congenital heart defects including pulmonary stenosis (PS), pulmonary atresia, tetralogy of fallot, hypoplastic left heart syndrome (HLHS), total anomalous pulmonary venous return (TAPVR) and others. Cyanosis occurs from either a decreased blood flow to the lungs or a mixing of oxygenated and non-oxygenated bloods. Low blood pressure may also indicate a congenital heart defect. Mild defects may be diagnosed during routine pediatric office visits when children exhibit symptoms such as breathing difficulties, feeding problems, or poor weight gain.

Medical Tests Used to Diagnose Congenital Heart Defects

• Chest x-ray: A chest x-ray images the heart and surrounding thoracic anatomy, shows heart size and shape and reveals whether the heart is misshapen or enlarged due to disease. Abnormal calcification (hardened blockage due to cholesterol build up) in the main blood vessels and fluid in the lungs (possible indication of congestive heart failure) can also be seen. Chest x-rays can also be used to image pacemakers and artificial heart valves to check for correct positioning.

• Electrocardiogram (ECG or EKG): An electrocardiogram is a graphical record of the electrical activity of the heart. A normal ECG, in most cases, rules out the presence of other cardiac diseases. An abnormal ECG indicates the presence of a cardiac disease and further investigations are performed. An ECG can be beneficial in detecting the disease and sometimes even the extent of the disease.

• Echocardiogram (heart ultrasound): This diagnostic technique is an excellent tool to provide details of the cardiac structures – vessels, valves, and muscle. Echocardiography is a non-invasive exam in which images are acquired and viewed in real time without the use of radiation. Echocardiography is often useful in studying the beating heart and provides some information on functional abnormalities of the heart wall, valves and blood vessels. Echocardiography with Doppler is used to measure blood flow across valves, across septal defects (shunts), extent of regurgitations, etc. Color flow mapping capability is extremely useful in the detection of shunts. Abnormal operation of the valves can be detected by studying the opening and closing function versus normal valve function. Echocardiography may also be used to study congenital heart defects such as a septal defect (a hole in the wall that separates the two chambers of the heart).

• Coronary angiography: In addition to diagnosing coronary artery disease (CAD) and congestive heart failure (CHF), angiography is useful for diagnosing or treating children with congenital heart diseases. Angiography can also image the beating heart in real time and may be useful in evaluating the function of the heart chambers. The procedure is a minimally invasive procedure and involves placing a catheter into a major blood vessel and injecting a dye to create an image of the heart and coronary arteries. Angiography is often used for diagnosing heart disorders, but is also a valuable tool for guiding therapeutic treatment of the coronary arteries. Angiography is an excellent tool for imaging blockages in the coronary vessels. It may also be used during pacemaker implantation to help position the pacemaker leads.

Updated: August 2006