Congenital Heart Defect: Recognize Heart Abnormalities in Babies

Congenital heart defect (CHD) occurs in approximately 1% of live births, or 8 out of every 1000 births. Approximately 25,000 infants are born each year with CHD, and more than 1,000,000 infants reach adulthood and live in the United States with functionally significant CHD.

Congenital heart defects can be detected when the heart is no larger than a peanut and is fully developed. In most babies with CHD, there is speculation that genetic factors play a role in the development of the defect, but the inheritance pattern is still unclear.

Secara umum, congenital heart defect divided into two main groups, namely Acyanotics Congenital Heart Defect dan Cyanotic Congenital Heart Defect. Cyanotic causes oxygen saturation in the blood to decrease, while Acyanotic does not change the oxygen saturation in the blood. Lesions acyanotic can cause problems with blood flow blockage to the heart chambers (pressure problems) or problems with the volume of blood flowing through the heart chambers back to the lungs (volume problems).

Acyanotics Congenital Heart Defect

Acyanotics Congenital Heart Defect (A-CHD) causes an increase in the volume of blood flowing to the lungs. This indicates contact between the systemic and pulmonary sides of the heart and results in a return flow of fully oxygenated blood to the lungs. Heart defects that include A-CHD include atrial septal defects (ASDs), ventricular septal defects (VSDs), atrioventricular septal defects (AVSDs), and patent ductus arteriosus (PDA).

1. Atrial Septal Defects (ASD)

In ASD, there is a hole in the wall that separates the atria. This is caused by a patent foramen ovale, an oval-shaped hole in the wall of the atrium that is supposed to close shortly after birth. The foramen is naturally present in the atrial septum in the womb that connects the right and left atria and should close shortly after birth. However, a condition called ostium secundum can occur if the foramen ovale is larger than it should be, or if the flap of tissue that should close the foramen is displaced or lacking. This causes the foramen to not close and there is a leak in the wall that separates the atria. Without closure and continuing for years, low pressure at the atrial level will cause the right atrium and ventricle to gradually enlarge. Symptoms of ASD are usually a heart murmur, an overactive right ventricle, and an enlarged pulmonary artery.

2. Ventricular Sepal Defects (VSD)

The ventricular wall is made up of three distinct areas that fuse together to form a single solid muscular wall of the ventricle. A VSD occurs when there is a hole in the ventricular wall. With a VSD, some of the oxygen-rich blood in the left ventricle that should be pumped to the body through the aorta is pumped directly into the right ventricle through the hole in the ventricular wall. When the hole is large, a lot of blood will go into the lungs, causing them to become congested and short of breath. A large amount of blood will back up from the lungs to the left heart, which then becomes overburdened and eventually enlarges. When a VSD is large, symptoms may include dyspnea, difficulty feeding, poor growth, excessive sweating, recurrent lung infections, heart failure in early infancy, respiratory distress, and failure to thrive.

3. Atrioventricular Septal Defect (AVSD)

AVSD is a heart defect where there is a hole between the right and left chambers of the heart, and the valves that control blood flow between the chambers may not form properly. Complete AVSD involves the part of the heart where the atrial wall meets the ventricular wall and the heart valves (mitral/tricuspid). This results in a large hole that spans the wall of the heart with one large valve on either side. Symptoms include pulmonary congestion and pulmonary hypertension. As a result, the child becomes thin due to the increased work of breathing. This is associated with down syndrome, and about 25% of people with down syndrome have AVSD.

4. Patent Ductus Arteriosus (PDA)

PDA is a heart defect that occurs when there is a connecting channel between the aorta and pulmonary artery. The ductus arteriosus (DA) is the normal pathway for fetal blood circulation that connects the pulmonary artery and the descending aorta. This channel is actually present at birth, but it will close as the baby grows. When the amount of oxygen in the blood increases after birth, the body stops producing prostaglandin E1, which keeps the DA open, and the DA will close a few hours after birth and close permanently within the first few weeks. In PDA, this channel does not close and eventually causes blood flow in the aorta and pulmonary artery. PDA is associated with maternal rubella and prematurity. The difference in pressure between the left and right sides of the heart causes too much blood to enter the lungs. Symptoms depend on the size of the opening and the degree of prematurity. A large opening can cause pulmonary congestion, CHF, and edema.

Cyanotic Congenital Heart Defect

Cyanotic Congenital Heart Defect (C-CHD) causes decreased oxygen saturation in the blood. The hallmark symptom of this condition is cyanosis, a condition of oxygen deficiency that causes the lips, fingernails, and fingertips to turn bluish. Due to chronic arterial oxygen desaturation, the body stimulates erythropoiesis or increased red blood cell production, resulting in polycythemia. Polycythemia is a condition of excess red blood cells, which increases blood viscosity and increases the risk of cerebrovascular and microvascular problems in the individual. Cyanotic Congenital Heart Defects include tetralogy of Fallot (TOF), double-outlet right ventricle, and hypoplastic left heart syndrome

1. Tetralogy of Fallot (TOF)

TOF has four basic components and is the most common cyanotic congenital heart defect. 1 The first basic component is a large VSD with blood mixing freely between the ventricles. The second component is pulmonary stenosis, which causes obstruction of the lung or blockage of the right ventricular outflow tract. The third component is the aorta lying over the VSD (called overriding aorta). Finally, right ventricular hypertrophy occurs due to increased pressure due to obstruction of the right ventricular outflow tract. Blood flow to the pulmonary artery is obstructed, so that oxygen-poor blood is more easily drawn into the aorta than into the pulmonary artery. The result is low oxygen levels in the arteries and body tissues. This results in cyanosis with symptoms of fatigue, fainting, and shock.

2. Double-outlet Right Ventricle

In Double-outlet Right Ventricle, the aorta and pulmonary artery arise from the right ventricle. The only way out of the left ventricle is through the VSD to the right ventricle.

3. Hypoplastic Left Heart Syndrome

Hypoplastic Left Heart Syndrome is the most serious congenital anomaly with the poorest prognosis. A mild defect is defined as a small left ventricle with some blockage. A severe defect is defined as a small left ventricle and absence of the mitral and aortic valves (atresia). Symptoms are usually minimal until the ductus arteriosus closes and the newborn develops shock and multiorgan failure.

Mortality rates in infants with CHD have declined dramatically as a result of medical and surgical advances in their care. The decline in mortality has now shifted the focus from mortality to the neurodevelopmental status of the individual and associated developmental delays. CHD is therefore the result of genetic inheritance, maternal conditions, and environmental factors, all interacting during a critical stage of heart development—the first 8 to 10 weeks of pregnancy. There are many types of CHD, each with its own risks and relative frequency. To understand the various CHDs, we need to have a clear understanding of normal heart development, anatomy, and physiology.

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