Atrial septal defect – Diagnostics – Overview of Information and Clinical Research

An atrial septal defect is a heart condition that people are born with, creating an opening between the heart’s upper chambers that can sometimes go unnoticed for years. This hole allows blood to flow in the wrong direction, which may seem harmless at first but can gradually affect how the heart and lungs work. Finding out whether this opening is small enough to monitor or large enough to require treatment starts with understanding how doctors identify and evaluate this condition.

Introduction: Who Should Seek Diagnostics

Diagnosing an atrial septal defect is not always straightforward because many people, especially children, show no obvious signs of having this condition. Some babies are born with the defect and it is discovered during routine checkups, while others may not learn about it until they reach adulthood. The most common scenario is that a doctor notices something unusual while listening to the heart with a stethoscope, which is a medical tool that allows healthcare providers to hear internal body sounds.^[1]

Parents should consider seeking diagnostic evaluation if their child experiences frequent respiratory infections, difficulty breathing during physical activity, or unusual tiredness when feeding in infancy. These symptoms might indicate that the heart is working harder than it should because extra blood is flowing through an opening in the wall between the upper heart chambers.^[2] Children who are not gaining weight as expected or who seem to tire easily compared to other children their age should also be evaluated by a healthcare provider.

Adults who have never been diagnosed with an atrial septal defect may start experiencing symptoms around age 40 or later. These can include shortness of breath during physical activity, a sensation of feeling the heartbeat (called heart palpitations), extreme fatigue, or swelling in the legs, feet, or belly area.^[1] Some adults may notice they become dizzy or light-headed, or they may experience a fast heartbeat without an obvious reason. If any of these symptoms appear, it is important to consult a doctor who can determine whether further heart testing is needed.

In many cases, an atrial septal defect is discovered accidentally during an examination for another health issue. A healthcare provider may detect a heart murmur, which is a whooshing sound that occurs when blood is not flowing smoothly through the heart. This murmur is often the very first clue that something may be different about the heart’s structure.^[5] However, not all murmurs mean there is a serious problem, and not all atrial septal defects create a murmur loud enough to be heard easily.

⚠️ Important

Very small defects, those measuring less than 5 millimeters, often do not cause any symptoms at all and may not put strain on the heart or lungs.^[2] In these cases, people may live their entire lives without knowing they have an atrial septal defect. However, larger openings can lead to complications over time, including increased risk of stroke, abnormal heart rhythms, and high blood pressure in the lungs, which is why timely diagnosis and monitoring are so important.

Even if a person feels perfectly healthy, it is still advisable to undergo diagnostic testing if a heart murmur is detected or if there is a family history of congenital heart defects. Some atrial septal defects are linked to genetic conditions or may run in families, so people with relatives who have had heart defects should inform their doctor.^[4] Early detection allows doctors to monitor the condition and decide whether intervention is necessary before complications develop.

Diagnostic Methods to Identify the Defect

The process of diagnosing an atrial septal defect usually begins with a physical examination. During this exam, a doctor will listen to the heart and lungs, check the pulse, and look for any signs of swelling or breathing difficulties. If the doctor hears a heart murmur or suspects a problem based on symptoms, several tests can be ordered to confirm whether an atrial septal defect is present and to determine its size and location.^[9]

Echocardiogram: The Main Diagnostic Tool

The most important test used to diagnose an atrial septal defect is called an echocardiogram. This test uses sound waves to create moving pictures of the heart, allowing doctors to see the structure of the heart chambers, the walls that divide them, and the valves that control blood flow. An echocardiogram can show whether there is a hole in the wall between the upper chambers and how much blood is flowing through that hole.^[9] This test is painless and does not involve any radiation, making it safe for people of all ages, including babies and pregnant women.

During an echocardiogram, a technician will place a small device called a transducer on the chest. This device sends sound waves into the body and picks up the echoes that bounce back from the heart. A computer then uses these echoes to create detailed images on a screen. The entire procedure usually takes less than an hour, and patients can return to their normal activities immediately afterward.

Sometimes, a special type of echocardiogram called a transesophageal echocardiogram may be needed to get a clearer view of the heart. This involves inserting a thin tube with a transducer on the end into the esophagus, which is the tube that connects the mouth to the stomach. Because the esophagus is located right behind the heart, this approach provides very detailed images of the heart’s structure. This test requires some preparation, such as fasting beforehand, and may involve light sedation to keep the patient comfortable.^[7]

Chest X-Ray

A chest X-ray is another common test that can help diagnose an atrial septal defect. This imaging test uses a small amount of radiation to create pictures of the heart and lungs. If an atrial septal defect is present, especially a larger one, the X-ray may show that the heart is enlarged or that there is increased blood flow to the lungs.^[9] However, a chest X-ray alone cannot confirm the diagnosis; it usually serves as a starting point that leads to more detailed testing.

Electrocardiogram

An electrocardiogram, often shortened to ECG or EKG, is a quick and painless test that records the electrical activity of the heart. Small sticky patches called electrodes are placed on the chest, arms, and legs, and these patches are connected to a machine that measures the heart’s electrical signals. The test shows how fast the heart is beating and whether the heart’s rhythm is normal or irregular.^[9]

An electrocardiogram can reveal signs that the right side of the heart is working harder than normal, which can happen when extra blood flows through an atrial septal defect. It can also detect abnormal heart rhythms, which sometimes develop in people with this condition. The test takes only a few minutes and results are available immediately.

Cardiac Magnetic Resonance Imaging (MRI)

If other tests do not provide enough information, a doctor may order a cardiac MRI. This imaging test uses powerful magnets and radio waves to create detailed pictures of the heart. Unlike X-rays, an MRI does not use radiation. Instead, the patient lies inside a large tube-shaped machine while images are taken. The test can show the exact size and location of an atrial septal defect and help doctors see how blood is flowing through the heart.^[9]

A cardiac MRI usually takes about 30 to 60 minutes. Patients need to lie very still during the test, and the machine can be noisy, but earplugs or headphones are often provided. Some people may feel uncomfortable in the enclosed space, but the test is safe and provides very valuable information about the heart’s structure and function.

Computerized Tomography (CT) Scan

A CT scan of the heart uses a series of X-rays taken from different angles to create detailed cross-sectional images. A computer then combines these images to produce a three-dimensional picture of the heart. This test may be used if other imaging tests do not give enough detail to make a diagnosis.^[9] A CT scan is faster than an MRI but does involve exposure to radiation, so it is used selectively.

Cardiac Catheterization

In some cases, especially when other tests are inconclusive or when more precise measurements are needed, doctors may perform cardiac catheterization. This is a more invasive procedure in which a thin, flexible tube called a catheter is inserted into a blood vessel, usually in the groin or arm, and guided to the heart. Dye is injected through the catheter, and X-ray images are taken to show how blood flows through the heart and whether there are any abnormalities.^[7]

Cardiac catheterization can also measure the pressure inside the heart chambers and the blood vessels in the lungs. This information helps doctors understand whether the atrial septal defect is causing problems such as increased pressure in the lungs, a condition known as pulmonary hypertension. The procedure is usually done under local anesthesia with mild sedation, and patients may need to stay in the hospital for observation afterward.

⚠️ Important

A Doppler study, which is often performed as part of an echocardiogram, uses sound waves to assess how much blood is moving between the heart chambers.^[7] This is an important measurement because it helps doctors determine the severity of the defect. A large amount of blood flowing through the hole indicates that the defect is significant and may need to be closed, while a small amount of flow suggests the defect may not cause major problems.

Diagnostics for Clinical Trial Qualification

When patients with an atrial septal defect are being considered for enrollment in clinical trials, specific diagnostic tests and criteria are used to ensure that participants meet the study requirements. Clinical trials are research studies that test new treatments, devices, or procedures to see if they are safe and effective. For trials involving atrial septal defects, researchers need to carefully select patients whose condition matches the goals of the study.

Before a patient can join a clinical trial, a comprehensive evaluation is usually required. This typically includes a detailed echocardiogram to confirm the presence of an atrial septal defect and to measure its size and location. The echocardiogram also helps determine how much blood is flowing through the defect, which is expressed as a ratio called the pulmonary-to-systemic flow ratio (Qp:Qs). A ratio greater than 1.5 usually indicates a significant defect that causes extra blood to flow to the lungs.^[16]

Clinical trials may also require patients to undergo cardiac catheterization to measure pressures inside the heart and lungs. This is especially important for studies evaluating new closure devices or surgical techniques, as the pressure measurements help researchers understand whether the defect is causing strain on the heart or damage to the blood vessels in the lungs. High pressure in the lungs, known as pulmonary hypertension, can affect whether a patient is a good candidate for certain treatments.^[16]

An electrocardiogram is often required to check for abnormal heart rhythms or signs that the right side of the heart is enlarged. These findings can influence whether a patient is eligible for a trial and may also help researchers track changes in heart function during the study. Similarly, chest X-rays or CT scans may be used to assess the size of the heart and the condition of the lungs.

Age is another factor that can affect eligibility for clinical trials. Some trials focus on children and young adults, while others are designed for older adults who have lived with the defect for many years. The timing of diagnosis, the presence or absence of symptoms, and the patient’s overall health are all taken into account when determining whether someone is a suitable candidate for a specific study.

In addition to imaging and functional tests, clinical trials may require blood tests to check for other health conditions that could affect the study results. For example, tests to measure kidney function, blood clotting ability, or the presence of infections may be needed. Some trials also require participants to have a certain level of physical activity tolerance, which may be assessed through exercise testing or questionnaires about daily activities.

Participation in a clinical trial also involves informed consent, which means that patients must fully understand the purpose of the study, the procedures involved, and any potential risks and benefits. Doctors and research staff will explain what diagnostic tests will be performed throughout the trial and how the results will be used to evaluate the treatment being studied. Patients have the right to ask questions and can choose to withdraw from the trial at any time if they change their mind.

Prognosis and Survival Rate

Prognosis

The outlook for people with an atrial septal defect varies depending on the size of the defect, when it is diagnosed, and whether it is treated. Very small defects, those measuring less than 5 millimeters, often do not cause any symptoms and may close on their own during childhood without needing treatment.^[7] Many people with small defects live normal, healthy lives and may never experience complications related to the condition.

For larger defects that do not close naturally, the prognosis depends on whether the defect is repaired and when the repair is performed. When an atrial septal defect is closed during childhood or early adulthood, before the heart and lungs have been significantly damaged, the chances of a full recovery are excellent. Most people who undergo repair at a young age have normal heart function afterward and can participate in regular physical activities without restrictions.^[2]

If an atrial septal defect is left untreated, especially a larger one, complications can develop over time. These include abnormal heart rhythms, particularly a condition called atrial arrhythmia, which can cause the heart to beat irregularly. The risk of stroke also increases because a blood clot could form in the heart, pass through the defect, and travel to the brain. High blood pressure in the lungs, known as pulmonary hypertension, can develop as well, which strains the right side of the heart and can lead to heart failure.^[6]

Even in older adults, closing an atrial septal defect can improve symptoms and reduce the risk of complications. Studies have shown that repair of the defect, whether through surgery or a catheter-based procedure, can lead to better quality of life and prevent further damage to the heart and lungs. However, if the defect has already caused severe pulmonary hypertension or other irreversible damage, the benefits of closure may be limited, and the risk of the procedure may be higher.^[16]

Long-term follow-up is important for people who have had an atrial septal defect repaired. Although most people do well after closure, some may still develop heart rhythm problems or other complications later in life, especially if the defect was repaired in adulthood. Regular checkups with a heart doctor help ensure that any new issues are detected and treated early.^[2]

Survival rate

For people with small atrial septal defects that do not cause symptoms and do not require treatment, life expectancy is generally normal. These individuals can live full, healthy lives without any significant impact on their survival. In fact, many people with small defects never even know they have the condition unless it is discovered during a medical exam for another reason.^[2]

When larger atrial septal defects are repaired early, particularly before age 25, the survival rate is excellent. Studies have shown that closing the defect at a young age, when the pressure in the lungs is still normal, leads to outcomes that are very close to those of people without heart defects. The risk of death from the repair procedure itself is very low, with surgical mortality rates for uncomplicated atrial septal defects being less than 1 percent in both children and adults.^[4]

For people whose atrial septal defects are not repaired, survival depends on the size of the defect and whether complications develop. Smaller defects that do not cause symptoms may not significantly affect life expectancy, but larger defects can lead to serious problems over time. Without treatment, large defects can shorten life expectancy due to complications such as heart failure, pulmonary hypertension, and stroke. However, even in elderly patients with large defects, surgical closure can be performed at low risk and can improve both survival and quality of life.^[16]

Overall, the key factor in determining survival is whether the defect is causing strain on the heart and lungs and whether it is treated before irreversible damage occurs. Early diagnosis and timely intervention are critical to ensuring the best possible outcomes for people with atrial septal defects.

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Atrial septal defect – Diagnostics

Introduction: Who Should Seek Diagnostics