Brain & Nervous System Stroke What Is Atrial Septal Aneurysm? By Jose Vega MD, PhD Jose Vega MD, PhD LinkedIn Jose Vega MD, PhD, is a board-certified neurologist and published researcher specializing in stroke. Learn about our editorial process Updated on March 29, 2022 Medically reviewed Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Claudia Chaves, MD Medically reviewed by Claudia Chaves, MD Claudia Chaves, MD, is board-certified in cerebrovascular disease and neurology with a subspecialty certification in vascular neurology. Learn about our Medical Expert Board Print Table of Contents View All Table of Contents Symptoms Causes Diagnosis Treatment The atrial septum is a membrane that separates the upper left and upper right chambers of the heart, called the atria. If the septum weakens or bulges, as can occur because of a heart defect, it can push into these spaces. This is known as an atrial septal aneurysm (ASA). An ASA keeps the heart from working properly and from pumping blood that returns to the right atria to pick up oxygen back out to the body. The condition is one possible cause of stroke, a potentially life-threatening blockage of blood flowing to the brain. This article looks at how an ASA is linked to having a stroke, as well as its connection to other health issues. It also discusses how this type of aneurysm may be treated. Morsa Images / Getty Images Atrial Septal Aneurysm Symptoms Symptoms of an atrial septal aneurysm are similar to those seen in other congenital heart defects, such as shortness of breath or fatigue. However, there may be no symptoms at all. Complications An atrial septal aneurysm increases the risk of stroke or a transient ischemic attack (TIA), a so-called "mini" or "warning" stroke. It is particularly linked to cryptogenic strokes, or those without a known cause, which are also associated with genetic heart conditions like mitral valve prolapse and abnormal heart rhythms like atrial fibrillation. Up to 40% of strokes have no known origin. Stroke symptoms are different from those of ASA and include: Facial droopingSpeech changesDifficulty moving or walkingVision changesChange in mental statusHeadaches These are signs that immediate medical help is needed. Tests That Determine Your Stroke Risk Causes A developing fetus has a hole in the heart wall that usually closes at birth when it starts breathing on its own. When the hole never closes the way it should, it's called a patent foramen ovale (PFO). ASA is often linked to this heart defect. PFO happens in about 25% of the population. Most cases don't cause any serious problems. Still, the hole in the heart wall allows blood to pass between the chambers, and an already weakened septum can develop an aneurysm. ASA is far more rare than PFO, but it's linked to the heart defect in at least 60% of cases. A September 2021 review looked at 12 studies to evaluate these kinds of atrial septal abnormalities and to better understand the link between atrial issues and cryptogenic stroke. The risk of stroke was higher in people with ASA, as well as those with atrial fibrillation heart rhythms. But the study wasn't definitive, with the authors noting only that these atrial weaknesses may cause stroke. Risk Factors for Atrial Fibrillation Diagnosis Imaging is key to an ASA diagnosis. An ASA appears as an unusually large 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. Treatment It may seem obvious to just surgically close a PFO because there's such a strong link between the defect and an ASA. But many people live with a PFO without issue, and doctors continue to disagree about the benefits of such a procedure. Medication is another treatment approach. If a doctor thinks a person with an ASA is at high risk for stroke, or if one has already occurred, they may want to try drugs that prevent blood clots and other strategies that will limit stroke risk. The Controversy Behind Closed PFOs Summary For many people, an ASA may happen because they already had an underlying condition at birth. They may not even know that they have an ASA for a long time or possibly ever. But it does increase the chance of having a stroke, so it's important to know the signs and symptoms. If you have concerns about a congenital heart problem and its risks, let your doctor know. A Word From Verywell Some cases of congenital heart conditions persist without affecting people much. This may be so much so that people come to consider them "minor" heart issues—or forget about them entirely. It's important, however, that your doctor know about them. Aside from the risk of ASA, these defects can cause other concerns as well. If you're not sure if your heart defect is part of your medical record, ask your healthcare provider. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 6 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Razaq M, Parihar RK, Saini G. Atrial septal aneurysm and stroke. Ann Pediatr Cardiol. 2012;5(1):98-9. doi:10.4103/0974-2069.93726 Yaghi S, Elkind MS. Cryptogenic stroke: A diagnostic challenge. Neurology: Clinical Practice. 2014;4(5):386-393. doi:10.1212/cpj.0000000000000086 Centers for Disease Control and Prevention. Stroke Signs and Symptoms. Reviewed August 28, 2020. Ioannidis SG, Mitsias PD. Patent foramen ovale in cryptogenic ischemic stroke: direct cause, risk factor, or incidental finding? Front Neurol. 2020;0. doi: 10.3389/fneur.2020.00567 Sun H, Zhou C, Xu L, Xu T. A meta-analysis of the association of atrial septal abnormalities and atrial vulnerability. Medicine. 2021;100(35):e27165. doi: 10.1097/md.0000000000027165 Menardi AC, Ribeiro PJ, Evora PR. Atrial septal aneurysm and atrial septal defect association – an uncommon but well-recognized association. Brazilian Journal of Cardiovascular Surgery. 2021. doi:10.21470/1678-9741-2020-0464 Additional Reading American Stroke Association. About Stroke.