Introduction

Definition of coronary heart disease

Coronary heart disease is a heart problem in which arteries of the heart are unable to supply enough oxygenated blood (blood rich in oxygen) to the heart. It is also known as coronary artery disease (CAD) or ischemic heart disease. CAD impacts the larger coronary arteries of the heart and is caused by narrowing or blockage of the coronary arteries.¹

Distinguishing adult coronary heart disease from congenital heart disease

Coronary heart disease in adults occurs due to the development of fatty substances in the coronary arteries. This interrupts or blocks the supply of oxygen-rich blood to the heart. These fatty deposits are called atheroma and this process is called atherosclerosis. 

Congenital heart disease includes heart abnormalities or defects present at birth. Congenital implies the defect forms when the foetus is developing and is present during the birth of a child. These conditions prevent proper blood flow in the heart and are also known as congenital heart defects².

Purpose of discussion

Abnormality of the coronary arteries occurs rarely in children. Congenital coronary abnormality or coronary heart disease can be isolated or accompanied by other congenital heart defects, such as pulmonary atresia, fallot's syndrome and transposition of the great arteries. Congenital heart diseases can be mild to serious. Mild heart diseases are not noticed until a child reaches adulthood. In contrast, some heart diseases are never noticed with symptoms. 

Advancements in the diagnosis and treatment of such diseases have improved results for people born with heart diseases. Among people with congenital coronary disease, more than 90% of them are treated in childhood and live into adulthood. Coronary heart disease whether occurs by birth or is diagnosed later, requires lifelong medical help to monitor the condition. This article discusses congenital heart diseases including coronary heart disease, its types, symptoms, diagnostic methods and treatment available to overcome this problem.

Understanding congenital heart disease (CHD)

Congenital heart disease

Congenital heart disease (CHD) is an abnormality in the functioning (structure) of the heart that is present at birth.¹⁰ These obstruct normal blood supply and include:

1. Problems with the heart valves controlling the blood flow
2. A hole in the heart wall or septum (separating the right and left sides of the heart)
3. Abnormal blood vessels (may range from too many to few, change in blood flow and in different directions)

In some cases, CHD is mild or simple and remains asymptomatic (without symptoms). But in severe cases, it can be life-threatening and need treatment in early childhood. Healthcare providers may diagnose heart defects early (foetus) or shortly after birth. 

Common types of congenital heart defects

There are different types of congenital heart defects. They vary from mild to complex and severe or critical. Mild or simple heart defects may not require any surgery and revive on their own. Sometimes, these defects are asymptomatic such as atrial and ventricular septal defects, pulmonary stenosis and patent ductus arteriosus which are mentioned below. 

Complex and severe defects can be life-threatening and need immediate treatment. In such cases, infants have low levels of oxygen, like in fallot's Syndrome and require surgery within one year of birth⁽³⁾. Congenital heart defects of different types are:

• Atrial Septal Defect (ASD): In this, a hole is present in the heart wall between the left and right atrium, (the upper two chambers of the heart). Due to this, blood flows from the left atrium to the right atrium and mixes there instead of circulating to the rest of the body.
• Ventricular Septal Defect (VSD): Here, a hole is present in the wall between the left and right ventricles (the lower two chambers in the heart). It causes the blood to flow from the left to the right ventricle. The blood mixes with the blood of the right ventricle and prevents circulating to the rest of the body. If the size of the hole is large, then the heart and lungs are required to work harder for blood circulation.
• Tetralogy of Fallot: It is a rare and complex congenital heart disease. A child born with this condition may have four different heart problems.
• Patent Ductus Arteriosus (PDA): This is a common type of congenital heart disorder. In this, a connection between two major arteries of the heart (the aorta and the pulmonary artery) does not close accurately. This results in an opening which allows blood to flow inappropriately.
• Transposition of the Great Arteries (TGA): It is a rare and severe heart disease where the two major arteries leaving the heart get reversed.

Coronary artery abnormalities in children

In children, abnormalities of the coronary arteries occur very rarely. Congenital coronary abnormalities may exist isolated or with other congenital heart disorders (defects) as discussed above. The different types of coronary artery abnormalities include:

Anomalous coronary arteries

Anomalous coronary artery (ACA) is a disease in which the coronary artery has an abnormality or malformation. The coronary artery in this originates from an abnormal location, potentially causing restricted blood flow. However, there can be other defects in the coronary artery resulting in malfunctioning. ACA may occur with other congenital heart defects and may also be known as congenital coronary artery anomaly (CAA). ACAs are often not diagnosed at birth till adulthood due to a lack of appropriate symptoms.³Asymptomatic ACA in teens or adults may start with symptoms such as chest pain, heart failure or sudden cardiac arrest (beating of heart stops) or death before the condition is identified. An anomalous left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital condition where the left coronary artery arises from the pulmonary artery causing inadequate oxygenation of the heart muscle⁴. Coarctation of the aorta (COA) is another type of coronary artery disease that may present at birth. The aorta is narrower than its actual normal size, which results in less oxygenated blood being sent to the body.

Coronary artery fistula

Coronary artery fistula refers to an abnormal connection between a coronary artery and one of the heart chambers or another blood vessel. It occurs due to improper development of one of the coronary arteries. A coronary artery is a blood vessel that plays an important role in bringing oxygenated blood to the heart.  Here, fistula implies an abnormal connection and normally, coronary artery fistula is congenital (present at birth). The disease may develop after birth and may be caused by:

• An infection resulting in the weakening of the wall of the coronary artery or the heart
• Specific type of heart surgery
• Heart injury due to an accident or surgery

It is a rare condition and infants born with it may sometimes have other types of heart defects. This deformity leads to abnormal blood flow and complications in children, including heart failure if left untreated. Narrowing of the coronary arteries is called coronary artery stenosis in children. It is rare in newborns but can occur as part of complex congenital heart conditions. ^5,6The treatment of CHD requires recognition of symptoms and diagnosis which are given ahead before implementing a method for the revival of the heart.

Symptoms and diagnosis of coronary artery abnormalities in children

Symptoms

Symptoms associated with congenital heart defects depend on various factors and symptoms for newborns, which can differ from the of older children.⁷ These are also related to the type of abnormality, number and mild or criticality of the heart defect. Some of the common symptoms that occur in serious cases and soon after birth or after a few months include:

• Bluish or pale grey tone to skin, fingernails and lips. In different skin colours, these changes can be easy or hard to find.
• Swelling of the areas around the eyes, legs or belly.
• Heart murmurs (unusual sounds) may be heard between heartbeats. 
• Poor circulation of blood
• Rapid breathing
• Shortness of breath during feedings resulting in poor weight gain.

Mild congenital heart defects may not exist later in childhood. The symptoms in older children of congenital heart defects are:

• Easily getting short of breath during exercise or activity.
• Constantly feeling fatigued.
• Fainting during exercise (activity) or getting tired easily by physical activity.
• Swelling can occur in the hands, feet or ankles.

Diagnostic tools

Normally, congenital heart defects are detected during pregnancy or in the first few months after birth. While others may remain undiagnosed until adulthood. Physical examination is performed by doctors to find out the symptoms of the disease. Based on the observation, tests are performed to confirm the diagnosis which is mentioned below.⁸

• Echocardiography or Echo: It is a painless test and helps to diagnose structural heart abnormality. This is used during pregnancy and helps to find CHD in a fetus
• Electrocardiogram (ECG): Helpful in assessing heart rhythm and function
• Cardiac catheterisation: Invasive procedure to evaluate blood flow and pressure in the heart and coronary arteries. It helps to analyse whether blood is flowing from the left side into the right side of the heart instead of circulating to the different parts of the body from the left side
• Chest X-ray: Analyse whether the heart is normal or enlarged. It also displays whether the lungs consist of extra fluid or blood flow, which may be implied as a sign of heart failure
• Cardiac MRI/CT:  Diagnose heart defect or monitor progress over time
• Genetic testing:  Determine whether a particular gene or genetic condition is responsible for the defect
• Pulse oximetry: Aids to estimate oxygen present in the blood

The symptoms are helpful in detecting children born with coronary heart disease. The diagnosis performed using such techniques assists in treating children. In addition, finding causes will provide opportunities to diagnose and treat children in the future efficiently.

Causes for coronary artery diseases in children

Congenital heart defects including coronary heart diseases occur due to abnormal development of the heart during the development of the baby in the womb. Doctors are unable to find the exact reason for these heart defects. While, researchers report that genes may be responsible along with other factors such as environment, maternal health or use of drugs and smoking.⁹ The causes of coronary heart disease or abnormality in children are:

• Genetic syndromes: Certain genetic conditions such as Down syndrome, and Noonan syndrome are associated with coronary heart defects
• Maternal health and environmental exposures: Maternal diabetes, viral infections during pregnancy (e.g., rubella), and certain medications may increase risk
• Congenital heart defects in family members: Increased likelihood of coronary abnormalities if family members have congenital heart disease

Coronary heart defects occur due to mutations (changes) in the DNA of a child. Moreover, the mutations that take place in the DNA may or may not be inherited from the parents. Rarely, a particular gene responsible for coronary heart defects is inherited from the parents. This implies that a parent with a coronary heart defect can be more likely to give birth to a child with the defect. Symptoms and diagnostic tools help to detect the disease, while causes along with them aid in treatment which will be discussed now.

Treatments 

Treatment of coronary heart disease depends on the type and seriousness of it. Usually, mild congenital heart defects get better over time on their own and do not need treatment. However, critical cases often demand treatment. Different types of  treatments available for congenital heart defects including coronary heart disease are:

Surgical interventions

It includes heart surgery, where a surgeon works directly on the heart. It is performed for many other reasons such as to repair a hole, repair a valve, widen a blood vessel or complex defects in the heart. In some complex congenital heart defects, surgical procedures are not possible and need a heart transplant.³

Transcatheter procedures

These are minimally invasive techniques to repair coronary artery fistulas or other abnormalities. It is also known as cardiac catheterization and is commonly used to repair mild heart defects including atrial septal defects, if unable to get better over time. 

Medications

Medicines are used to manage symptoms of heart failure or improve heart function. Medications are often preferred when a child is born with a coronary heart defect or other congenital heart disease like patent ductus arteriosus. Usually, such a type of mild disease goes away over time. 

However, in some cases, medicine is required in infants such as indomethacin or ibuprofen, and acetaminophen. Medicines are also used to manage the functioning of the heart such as blood pressure drugs, water pills (remove fluid from the body and help to lower strain on the heart) and heart rhythm drugs or anti-arrhythmic (control irregular heartbeats).¹⁰

Long-term monitoring and care

Lifestyle changes may be suggested to maintain heart health and prevent complications when a child has congenital heart defects, including coronary heart disease. With proper care, many children can lead normal lives, though some may need a lifelong medical examination. Some monitoring parameters include:

• Regular cardiology follow-up: Ongoing evaluation of heart function, especially as children grow and develop
• Exercise or activity restrictions: Limitations on physical activity may be necessary depending on the severity of the condition
• Routine vaccination: Such diseases have immune problems, requiring vaccination to prevent infections

Living with such diseases may cause stress and anxiety in some children but advancement in diagnosis and treatment allows them to survive to adulthood in most cases. Children born with coronary heart disease are expected to live better lives today than in the past.

Summary

Coronary heart disease found in children at the time of birth is a type of congenital heart disorder that interferes with the supply of oxygen-containing blood to the heart. It affects the functioning of coronary arteries of the heart due to blockage or narrowing of them. The disease can be mild or severe, mild coronary heart disease gets better with time mostly. 

While severe or critical cases need treatment and long-term monitoring with care. Symptoms related to these disorders are not limited to changes in skin colour (bluish or pale grey), shortness of breath, or swelling in certain areas. While in some cases, the absence of symptoms causes simple diseases to be treated critically. Children with coronary artery abnormalities often do well with early diagnosis and appropriate treatment.