How Does an ASD Differ from Heart Failure?
At a Glance
An atrial septal defect (ASD) is a physical hole in the heart you are born with, while heart failure occurs when the heart muscle is too weak to pump effectively. Although an untreated ASD can mimic or eventually cause heart failure, repairing the hole often resolves the root problem.
In this answer
4 sections
Having an atrial septal defect (ASD) is not the same as having heart failure. An ASD is a structural abnormality—a physical hole in the wall between the two upper chambers of the heart that you are born with [1]. Heart failure, on the other hand, is a clinical condition where the heart muscle has become too weak or stiff to pump blood effectively to the rest of the body.
While they are fundamentally different, a large, untreated ASD can produce symptoms that mimic heart failure. Over many years, the extra strain can eventually lead to right-sided heart failure [2][3]. (Note: A patent foramen ovale, or PFO, is a small flap-like opening. Unlike a large ASD, a PFO rarely causes enough blood to leak back to stretch the heart, so it very rarely leads to heart failure on its own [4].)
The Overlap: Why the Symptoms Feel Similar
If you have an ASD, oxygen-rich blood from the left side of the heart leaks through the hole back into the right side [5]. In medical terms, this is called a left-to-right shunt. It means the right side of your heart and your lungs have to handle a much larger volume of blood than normal.
Because your right heart is working overtime to manage this chronic volume overload, you might experience symptoms that are nearly identical to early signs of heart failure [6]:
- Shortness of breath, especially when exercising or doing routine daily activities
- Fatigue or feeling easily exhausted [7]
- Palpitations or a racing heartbeat, which can be caused by atrial arrhythmias (like atrial fibrillation) resulting from the stretching of the heart chambers [8][9]
Later on, if the right side of the heart actually begins to fail, you might also experience significant swelling (edema) in your legs, ankles, or abdomen [10][11].
Structural Defect vs. Pump Failure
The best way to understand the difference is to think of the heart as a house with both plumbing and a water pump.
- Atrial Septal Defect (The Plumbing): With an ASD, the heart muscle (the pump) is initially healthy, but the “plumbing” has a leak. The extra blood volume causes the right-sided chambers—the right atrium and right ventricle—to stretch and enlarge to accommodate the constant extra load [12][13].
- Heart Failure (The Pump): Heart failure means the pump itself is broken. The heart muscle is compromised, meaning the left ventricle either can’t squeeze hard enough to push blood out, or is too stiff to relax and fill properly (a condition known as Heart Failure with preserved Ejection Fraction) [14].
Understanding Your Echo Report
If you read your echocardiogram report, you might see scary-sounding terms like right ventricular enlargement, right ventricular dilation, or right heart strain [15]. Because these terms are also used to describe heart failure, many patients panic. However, if you have a large ASD, this enlargement is an expected consequence of the plumbing leak. The right heart is remarkably resilient and stretches to handle the extra volume. Having an enlarged right ventricle on your echo does not automatically mean your heart is failing.
Can an ASD Cause Heart Failure?
Yes, but it typically takes a very long time. If a significant ASD is left untreated, the chronic volume overload takes a toll. The continuous stretching of the right ventricle places immense stress on the heart muscle [5]. Over many decades, this constant strain can finally cause the right heart to wear out and progressively fail, resulting in right-sided heart failure [2][16].
The excess blood flow can also damage the blood vessels in the lungs, leading to high blood pressure in the lungs (pulmonary hypertension) [17][18]. This extra resistance makes it even harder for the right ventricle to pump, accelerating the progression toward heart failure.
Why the Difference Matters for Treatment
Understanding this distinction is empowering: because an ASD is a structural problem, repairing the structure can often fix the root cause.
Many adults are diagnosed with an ASD after living with the defect for decades. Even then, closing the ASD stops the volume overload. This allows the right side of the heart to remodel and shrink back toward a normal size, significantly improving symptoms and reducing pulmonary pressures in many patients [19][20]. Heart failure treatments, by contrast, usually focus on lifelong medications to help the compromised heart muscle pump more efficiently.
After an ASD is closed, older adults may still need long-term follow-up to monitor for residual arrhythmias or lingering pulmonary hypertension, but correcting the structural leak is a critical step in protecting the heart [19].
Common questions in this guide
Is an atrial septal defect a type of heart failure?
Why do ASD symptoms feel similar to heart failure?
Does an enlarged right ventricle mean my heart is failing?
Can an untreated ASD eventually lead to heart failure?
Will closing my ASD reverse right heart enlargement?
Questions to Ask Your Doctor
Curated prompts to bring to your next appointment.
- 1.Is my right ventricle enlarged, or is it showing signs of strain? If so, is this reversible after closing the defect?
- 2.Does my ASD leak enough blood to cause significant volume overload?
- 3.Do I show any signs of pulmonary hypertension on my echocardiogram?
- 4.Are there any signs of atrial arrhythmias, like atrial fibrillation, that we need to monitor?
- 5.After the defect is closed, what kind of long-term follow-up will I need for my right heart or lung pressures?
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References
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This page explains the differences between an atrial septal defect and heart failure for educational purposes. Always consult your cardiologist for an accurate diagnosis and treatment plan tailored to your condition.
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