By Aditi Venkatraman and Aditya Venkatraman
Congenital heart disease (CHD) is a birth defect that affects around 200,000 children in the United States annually. In the United Kingdom, CHD affects up to 8 in every 1,000 babies, making it one of the most common birth defects in the country. Characterized by abnormalities in the structure of the heart, the disease causes disruptions to the blood flow through the heart, rapid breathing, fatigue, poor blood circulation, and cyanosis, which entails a bluish tint to the skin, nails, and lips of the affected child. Although most affected individuals exhibit these symptoms, some defects can show no signs or symptoms. Individuals with these defects are generally diagnosed with CHD when they are older. Furthermore, the severity of the disease is dependent on the type of defect and the impact it has on the heart. Consequently, children with more severe defects require treatment while those with less severe abnormalities do not. The type of treatment an individual with CHD receives depends on the type of defect, its severity, the child’s age, size and health, and availability. The structured study of CHD first started at a pediatric cardiology clinic started by Dr. Helen Taussig at Johns Hopkins Hospital in 1930, where she hypothesized that using an arterial to pulmonary artery shunt would solve symptoms of cyanosis in young children.
Figure 1: Demonstration of an arterial to pulmonary shunt, which helps increase the flow of blood from the arterial to a pulmonary artery of the heart (Source: Medina et al).
Through years of research on surgical techniques and treatment, physicians and researchers have developed techniques to alleviate the symptoms of CHD. However, there is no specific cure for the disease.
Recent research has demonstrated the possible role of genetics and the environment in the development of this birth defect. Through epidemiological studies, it was found that 20-30% of congenital heart disease cases involved either a genetic or environmental cause (Pierpont et al, 2018). Through next-generation sequencing (NGS), a DNA sequencing method that uses the concept of parallel processing, researchers found that cases that did have genetic causes were results of chromosomal anomalies/aneuploidy (8-10% of cases), autosomal dominant (8% of cases), inherited autosomal recessive variation (2% of cases), and single-gene disorders (3-5% of cases). Although the genetic mutations that are responsible for the disease have not been fully determined yet, researchers continue to use karyotyping, Fluorescence in situ hybridization (FISH, and other sequencing techniques (such as NGS). In order to complete these bioinformatic analyses and determine the true causes of the disease, which would then lead to established treatment, more money needs to be invested in this field of research. Along with the fact that early diagnosis leads to more accurate actual prevalence numbers, this is one of the many reasons why awareness for CHD needs to be raised.
Most patients with CHD generally exhibit the following symptoms:
Murmurs or abnormal heart rhythms
Shortness of breath in babies, especially during feeding
Swelling in the legs, stomach, and around the eyes
Blue tinge to the skin
Rapid breathing and heartbeat
It is important to note that some patients do not exhibit any of the physical symptoms mentioned above, which is arguably more dangerous and life-threatening because a lack of symptoms leads to late diagnoses. However, cardiologists can detect issues with an individual’s heart without them exhibiting any symptoms.
As mentioned previously, there is no cure for CHD but treatment is often critical for alleviating symptoms. The following methods of treatment are most common in treating patients for CHD:
Common surgical procedures: Patent ductus arteriosus (PDA) ligation, which involves the closing off of the opening of the ductus arteriosus; Coarctation of the aorta repair, in which a cut is made on the left side of the chest, between the ribs, to decrease the narrowness of the aorta; and Atrial septal defect (ASD) repair, which closes up any holes in the atrial septum as a result of a congenital defect (sometimes done via open-heart surgery).
Specialized physical activity: regular physical activity helps delay the progression of heart failure, coronary artery disease, and pulmonary hypertension.
Common medications: ACE inhibitors, which treat hypertension and congestive heart failure; Antiarrhythmics, which treat irregular heartbeats; Anticoagulants, which reduce the probability of clotting; Antiplatelets, which prevents thrombosis in patients who have stents, shunts, mechanical valves, etc.; and Diuretics, which lower blood pressure to reduce the amount of fluid in blood vessels, tissues, and lungs.
Because it is a congenital disease, CHD can be detected in the baby in the wound through a specialized ultrasound called fetal echocardiography. This can be done when the woman is 18 to 22 weeks pregnant, giving her the option to abort the child if that is the family’s final decision. There are other ways of detecting CHD in children postpartum, which include:
Electrocardiogram (ECG): records electrical signals in your heart, and can therefore diagnose irregular heart rhythms and blocked arteries.
Echocardiogram: ultrasound which creates images of an individual’s moving heart. This allows the cardiologist to see how the heart’s valves and chambers are pumping blood through the heart.
CT scans and MRIs: both of these exams create images of an individual’s chest.
Pulse oximetry: gives doctors a sense of how much oxygen is in the blood.
Congenital heart disease is an increasingly common birth defect around the world, and cases of the disease are negatively impacted by late diagnoses, which lead to skewed data for researchers, increased severity of the defect, and worsened symptoms. By writing these blog articles, we hope to shine some light on diseases such as CHD, in hopes to raise awareness and encourage early detection.
Here are some links where you can either get involved in CHD-related organizations for this disease or make donations that will further CHD research:
Organizations
Donation Links
References
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