Definition & Overview
Congenital heart disease (CHD) is a general medical term used to describe a wide range of heart ailments that develop before birth largely due to abnormalities in cardiovascular structures such as the heart and the blood vessels around it. Affecting one in every 100 children, the defects are believed to be caused by maternal viral infection, genetic or chromosomal abnormalities, and taking certain medication during pregnancy. A congenital heart disease, depending on its type, can obstruct blood flow in the heart or affect the heart’s rhythm, making it a life-threatening disease. CHD causes more deaths in the first year of life when compared to other birth defects. The condition has resulted in 366,000 deaths in 1990. However, due to the availability of numerous medical advancements, the number of deaths has dropped to 323,000 in 2013.
Cause of Condition
The majority of congenital heart disease cases are caused by a combination of genetic and environmental factors. However, there are cases wherein the cause has yet to be established. For this reason, experts in the field continue to research and investigate the condition.
The most common known causes of CHD are sporadic genetic changes that typically involve the addition of segments or focal mutations of DNA. 5-8% of the cases are caused by large chromosomal abnormalities such as trisomies 21, 13, and 18. CHD is also common in families with a history of various genetic syndromes such as Down syndrome and those with a missing piece of genetic materials of chromosome 22. Genetic testing is recommended for pregnant women wherein a genetic counselor estimates the risk of the unborn child in developing CHD.
Meanwhile, taking certain medications during pregnancy and maternal viral infections during the first trimester of the pregnancy are considered risk factors. Maternal obesity also places children at a higher risk of developing specific congenital heart defects.
There is a long list of congenital heart diseases and their symptoms widely vary. The most common conditions are heart valve defects, atrial and ventricular septal defects, and abnormalities of the heart muscles. While different types can be treated following birth, most are considered to be life-threatening. Also some types of CHDs can go undetected throughout life while other patients exhibit fainting, cyanosis, shortness of breath, poor feeding, underdeveloped muscles and limbs, heart murmur, and respiratory infections. CHDs also have associated symptoms including anal atresia, vertebral and cardiovascular anomalies, tracheoesophageal fistula and atresia, and kidney anomalies.
Who to See & Types of Treatments Available
The majority of congenital heart defects are diagnosed through a pregnancy ultrasound, which doctors perform when abnormal heart sounds or heart murmurs are detected while listening to the fetus’ heartbeat.
In cases where the heart defects were not detected through routine exams during pregnancy but the child is showing symptoms mentioned above, the first medical professional to consult is a family doctor or GP. To obtain an accurate diagnosis, parents are asked about the child’s symptoms, the family’s medical history, the mother’s medical condition and whether or not she took specific medication while pregnant.
Various test will then be required including the following:
Echocardiogram – This is a noninvasive test that uses ultrasound technology to obtain images of the heart, allowing the diagnosing physician to assess the condition of the organ and identify any abnormalities.
Electrocardiogram – This is another noninvasive test performed to record the heart’s electrical activity to detect rhythm problems. This test uses electrodes that are connected to a computer that shows waves indicating how the heart is beating.
Chest X-ray – if the diagnosing physician suspects an enlargement of the heart, a chest x-ray will be ordered. This also allows the doctor to assess if there are unnecessary blood or fluid in the lungs, which could be a sign of a heart failure.
Pulse oximetry – congenital heart diseases can also be diagnosed by determining the amount of oxygen in the blood. In this test, a sensor is used to monitor the child’s 02 saturation by analyzing the pulsating nature of blood flow in the arteries and the light absorptive characteristics of hemoglobin.
Cardiac catheterization – If previous tests results prove to be inconclusive, cardiac catheterization will be performed. This is an invasive procedure that requires the insertion of a thin flexible tube into the blood vessel from the groin into the heart. This test provides a more detailed and accurate image of the heart when compared to other tests. Aside from being used as a diagnostic procedure, cardiac catheterization can also be used to perform treatment procedures.
Types of Treatments Available
Not all congenital heart defects require treatment as some types have no long-term effect and can safely go untreated; some may even correct themselves as the child ages. However, serious cases of CHD such as narrowed arteries and heart failure warrant immediate medical attention. Available treatments include the following:
Medications – less serious heart defects are treated or managed with medications including angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), beta blockers, and diuretics.
Cardiac catheterization – narrowed arteries as well as small holes in the heart, which were traditionally treated through an open-heart surgery, can now be corrected through minimally invasive procedure that involves inserting a thin flexible tube into a leg vein, which is then threaded until it reaches the heart. Through this procedure, conditions such as atrial septal defect can be treated by plugging the hole using an umbrella-like device. The same device can be used to widen blocked arteries to restore normal blood flow.
Open-heart surgery – Several types of congenital heart diseases have to be treated through an invasive open-heart surgery that requires opening the chest and temporarily stopping the heart from beating using a heart-lung machine.
Heart transplant. In cases that cannot be treated by open-heart surgery, a heart transplant is considered as the last option. Typically performed on patients with end-stage heart failure or severe coronary disease, this requires harvesting a healthy heart from a recently deceased donor and transplanting it into the patient. During the procedure, the surgeon has the option to remove the faulty heart or leave it in place to support the donor heart. As an invasive, highly delicate procedure, post-operative survival periods average 15 years.
Webb GD, Smallhorn JF, Therrien J, Redington AN. Congenital heart disease. In: Bonow RO, Man DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 65.