Atrial Septal Defects
Surgical and Transcatheter Management
Atrial septal defects represent a communication between the left and right atria (a hole between the upper chambers of the heart). Simple atrial septal defects were among the first congenital cardiac anomalies to be corrected by surgical treatment. The treatment of these defects was made much easier with the advent of cardiopulmonary bypass. In this article, we will attempt to provide a brief overview, and address the surgical and transcatheter management of common atrial septal defects. We will consider three major types of atrial septal defects: secundum, primum, and sinus venosus.
Secundum atrial septal defect is by far the most common, representing 80% of all ASD’s. It is caused by the failure of a part of the atrial septum to close completely during the development of the heart. This results in an opening in the wall between the atria (a "hole" between the chambers).
Primum atrial septal defects are part of the spectrum of the AV canals, and are frequently associated with a split in the leaflet of the valve, or so called cleft mitral valve.
The sinus venosus atrial septal defect occurs at the junction of the superior vena cava and the right atrium. This represents the floor of the right atrium where blood returns from the upper extremities and head to enter the right atrium. These may frequently be associated with anomalous drainage of the pulmonary veins. This means that one or more of the pulmonary veins, which normally carry oxygenated blood from the lungs back to the left atrium, enters the right atrium instead. There are numerous types of abnormal pulmonary venous connections.
When an atrial septal defect is present, blood can flow ("shunt") across the hole in the from the left atrium to the right atrium. This results in enlargement of the right atrium and right ventricle due to the "extra" blood flowing across the hole, and results in increased pulmonary blood flow.
An atrial septal defect (ASD) — sometimes referred to as a hole in the heart — is a type of congenital heart defect in which there is an abnormal opening in the dividing wall between the upper filling chambers of the heart (the atria). In most cases ASDs are diagnosed and treated successfully with few or no complications.
Atrial septal defect An atrial septal defect is an abnormal opening between the heart's upper chambers. It's a common congenital heart defect.
Chambers and valves of the heart The heart has two upper chambers — left atrium and right atrium — and two lower chambers — left ventricle and right ventricle. Valves control the direction of blood flow.
What Is an Atrial Septal Defect? To understand this defect, it first helps to review some basics about the way a healthy heart typically works.
The heart has four chambers: The two lower pumping chambers are called the ventricles, and the two upper filling chambers are the atria.
In a healthy heart, blood that returns from the body to the right-sided filling chamber (right atrium) is low in oxygen. This blood passes to the right-sided pumping chamber (right ventricle), and then to the lungs to receive oxygen. The blood that has been enriched with oxygen returns to the left atrium, and then to the left ventricle. It's then pumped out to the body through the aorta, a large blood vessel that carries the blood to the smaller blood vessels in the body. The right and left filling chambers are separated by a thin shared wall, called the atrial septum.
Kids with an atrial septal defect (ASD) have an opening in the wall (septum) between the atria. As a result, some oxygenated blood from the left atrium flows through the hole in the septum into the right atrium, where it mixes with oxygen-poor blood and increases the total amount of blood that flows toward the lungs. The increased blood flow to the lungs creates creates a swishing sound, known as a heart murmur. This heart murmur, along with other specific heart sounds that can be detected by a cardiologist, may be clues that a child has an ASD.
ASDs can be located in different places on the atrial septum, and they can be different sizes. The symptoms and medical treatment of the defect will depend on those factors. In some rare cases, ASDs are part of more complex types of congenital heart disease. It's not clear why, but ASDs are more common in girls than in boys.
Signs and Symptoms of an ASD Infants and children with larger, more severe ASDs, however, may possibly show some of the following signs or symptoms:
The size of an ASD and its location in the heart will determine what kinds of symptoms a child experiences. Most children who have ASDs seem healthy and appear to have no symptoms. Generally, kids with an ASD feel well and grow and gain weight normally.
•shortness of breath
•lung problems and infections, such as pneumonia
If an ASD is not treated, health problems can develop later, including an abnormal heart rhythm (known as an atrial arrhythmia) and problems in how well the heart pumps blood. As kids with ASDs get older, they may also be at an increased risk for stroke, since a blood clot that develops can pass through the hole in the wall between the atria and travel to the brain. Pulmonary hypertension (high blood pressure in the lungs) may also develop over time in older patients with larger untreated ASDs.
Fortunately, most kids with ASD are diagnosed and treated long before the heart defect causes physical symptoms. Because of the complications that ASDs can cause later in life, pediatric cardiologists often recommend closing ASDs early in childhood.
Atrial Septal Defect
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