Atrial Septal Aneurysm: Signs, Symptoms, Complications

An atrial septal aneurysm (ASA) occurs when a bulge forms in the atrial septum, the membrane separating the heart's upper left and upper right chambers (atria). The atrial septum usually is relatively immobile, but it can sometimes enlarge, become hypermobile, and protrude into the left or right atrium.

Atrial septal aneurysms are relatively rare but can cause a stroke, a potentially life-threatening blockage of blood flowing to the brain. However, many people with ASA have everyday lives, mainly if the aneurysm is small.

This article discusses atrial septal aneurysms. It explains how an ASA is linked to a stroke and other health issues. It also describes how atrial septal aneurysms are diagnosed and treated.

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What Are the Symptoms of an Atrial Septal Aneurysm?

An atrial septal aneurysm does not typically cause any symptoms. It is often only detected during routine echocardiography or evaluation of ischemic stroke.

An echocardiogram often shows evidence of paroxysmal supraventricular arrhythmias (abnormal heart rhythms) in people with ASA.

ASA is also commonly associated with congenital heart defects, such as atrial septal defects (ASD) or patent foramen ovale (PFO).

If you have related heart problems, you may also experience the following symptoms:

Fatigue
Reduced exercise tolerance
Shortness of breath

Complications

Atrial septal aneurysm is linked to other heart defects and can increase your risk of ischemic stroke.

A 2021 review of 12 studies evaluating different atrial septal abnormalities found atrial septal aneurysm was associated with higher stroke rates. However, the study authors stressed that while atrial weakness may be a factor for stroke, the results are not definitive.

Stroke symptoms are different from those of ASA and include the following:

Facial drooping
Speech changes
Difficulty moving or walking
Vision changes
Change in mental status
Headaches

These are signs that immediate medical help is needed.

What Causes an Atrial Septal Aneurysm?

An atrial septal aneurysm is a type of heart defect present at birth. In utero, we all have a hole along the atrial septum dividing the left and right atria. The hole is known as patent foramen ovale (PFO).

The fetus obtains its blood supply from its mother, and this blood enters the right heart and shunts across the PFO to supply oxygenated arterial blood to the fetus's body.

Most of the time, the PFO closes after delivery upon spontaneous air breathing. However, in about a quarter of the population, the PFO doesn't close.

Most of the time, PFO does not cause any further problems. Sometimes, though, arterial pressure can cause a bulge to form in the atrial septum near the PFO. This is known as an atrial septal aneurysm.

How Is an Atrial Septal Aneurysm Diagnosed?

Imaging is vital to an ASA diagnosis. An ASA appears as an extensive and bulging membrane that moves between the two atria.

In many cases, a complete echocardiogram of the heart may be done if a person has a related congenital heart condition.

It also may be done if someone has a stroke and doctors are trying to find out why. They may look for blood clots in the left atrium, a PFO, a mitral valve prolapse, or the ASA.

A person's overall health and family history also are needed for a complete diagnosis. That's especially true if there is a personal history of strokes, TIAs, or other cardiovascular issues.

How Is an Atrial Septal Aneurysm Treated?

The vast majority of ASAs which are identified on echocardiography incidentally are benign, and no treatment is warranted.

If an ASA with an associated PFO or ASD is identified in the process of evaluating a patient with a stroke, then a complete workup is needed to ascertain the likelihood that the PFO or ASD might have contributed to the stroke.

Medication is another treatment approach. If a person with an ASA is at high risk for stroke, or if one has already occurred, they may be given drugs that prevent blood clots along iwth other strategies to limit stroke risk.

Summary

Most ASAs are incidentally found on an echocardiogram performed for other reasons. Thus, most patients with ASA have no symptoms, and the ASA is benign.

Small atrial level shunts are associated with ASA; in rare cases, these can be related to stroke. People may not even know that they have an ASA for a long time or possibly ever. But it increases the chance of a stroke, so knowing the signs and symptoms is essential.

If you have concerns about a congenital heart problem and its risks, talk to your healthcare provider.

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