Aortic regurgitation is a condition where the aortic valve, the one-way gate between your heart’s main pumping chamber and the large artery that carries blood to the rest of your body, doesn’t close all the way. Each time the heart relaxes between beats, some blood leaks backward into the pumping chamber instead of flowing forward. Over time, this forces the heart to work harder to push enough blood out, and the extra workload can eventually damage the heart muscle.
How the Valve Fails
The aortic valve normally has three thin flaps (called leaflets) that snap shut after each heartbeat to prevent backflow. In aortic regurgitation, those leaflets no longer seal tightly. The gap can result from problems with the leaflets themselves, from stretching of the artery wall where the valve sits, or from both. Blood that should be moving through your body instead sloshes back into the left ventricle, the heart’s largest and strongest chamber.
The left ventricle responds by stretching to hold the extra volume. Over years or even decades, the chamber gradually enlarges and its walls thicken. This remodeling allows the heart to maintain a normal output for a long time, which is why many people feel perfectly fine for years. But the adaptation has limits. Eventually, scar-like tissue (fibrosis) builds up in the heart muscle, stiffening the walls and weakening their ability to contract. Once that scarring is established, it doesn’t reverse, even after the valve is fixed.
Common Causes
The most common congenital cause is a bicuspid aortic valve, a valve born with two leaflets instead of three. It affects roughly 0.5 to 2 percent of the population, making it the most common heart defect present from birth. A bicuspid valve is more prone to leaking over time and also carries a higher risk of infection.
Infective endocarditis, an infection of the heart’s inner lining that often settles on valve tissue, is another major cause. In autopsy studies, endocarditis has been identified as the primary reason for aortic insufficiency in 15 to 40 percent of people with bicuspid valves. The infection erodes or perforates the leaflets, sometimes causing sudden, severe leakage. Other causes include age-related wear and calcification, rheumatic heart disease (still common in parts of the world with limited access to antibiotics), conditions that widen the aorta (such as Marfan syndrome or high blood pressure), and trauma to the chest.
Acute vs. Chronic: Two Very Different Experiences
Aortic regurgitation comes in two forms that feel and behave very differently. The chronic form develops slowly, often over years. Because the heart has time to adapt, you can remain symptom-free for a long time. When symptoms finally appear, they typically include shortness of breath during activity, feeling winded while lying flat, waking at night gasping for air, palpitations, fatigue, and occasionally chest pain or fainting.
The acute form is a medical emergency. It occurs when a valve that was previously working fine suddenly starts leaking heavily, often from an infection or a tear in the aorta. The heart has no time to stretch and adapt, so blood pressure inside the chamber spikes rapidly. Symptoms come on fast: cough, pounding heartbeat, difficulty breathing with exertion, and chest pain. Acute aortic regurgitation typically requires urgent surgery.
How It’s Diagnosed
A doctor may first suspect aortic regurgitation from physical exam findings. Chronic cases often produce a distinctive heart murmur, a high-pitched sound that fades during the resting phase of each heartbeat. Another telltale sign is a widened pulse pressure, meaning a large gap between the top and bottom numbers of a blood pressure reading. In some cases, a second murmur called an Austin Flint murmur appears: the backward jet of blood partially blocks the nearby mitral valve, creating a low rumbling sound.
An echocardiogram (heart ultrasound) confirms the diagnosis and measures how much blood is leaking. Doctors grade severity using several measurements. Severe aortic regurgitation is defined by specific thresholds: the opening through which blood leaks back is 0.30 square centimeters or larger, the volume of blood flowing backward per beat is 60 milliliters or more, and the fraction of blood leaking back is 50 percent or more. A measurement of the leak’s width (the vena contracta) greater than 0.6 centimeters also signals severe disease. These numbers help guide treatment decisions, but they’re tracked by your care team rather than something you need to memorize.
What Happens to the Heart Over Time
In chronic aortic regurgitation, the left ventricle initially compensates remarkably well. It enlarges in a pattern called eccentric hypertrophy, stretching outward to accommodate the extra blood. This allows normal pumping output for years, sometimes decades, with few or no symptoms.
Eventually the heart reaches a tipping point. Wall stress rises, and the muscle can no longer keep up by stretching alone. The walls begin thickening in an additional way, adding bulk to try to reduce stress, but this further increases the heart’s demand for oxygen and energy. Microscopic muscle cell injury starts to accumulate, and diffuse fibrosis, a subtle stiffening of the tissue, creeps in. At this stage, the heart may still appear to pump normally on imaging, but its reserve capacity is quietly eroding.
The classic sign that compensation is failing is a drop in ejection fraction, the percentage of blood the ventricle pushes out with each beat. Once ejection fraction begins falling from its previously stable level, the risk of heart failure and death rises significantly. Importantly, by the time scar tissue progresses to replacement fibrosis (essentially dead patches of muscle replaced by scar), the damage is irreversible. This is why guidelines focus on intervening before that point.
When Surgery Is Recommended
Both American and European cardiology guidelines agree on the core principles: surgery is recommended for anyone with severe aortic regurgitation who has symptoms, and for asymptomatic patients whose heart is showing signs of strain. The key triggers include an ejection fraction that drops to 55 percent or below (American guidelines) or 50 percent or below (European guidelines), and a left ventricle that has stretched beyond a certain size, specifically an end-systolic diameter greater than 50 millimeters.
Guidelines also recognize a gray zone. The American guidelines consider intervention reasonable when ejection fraction is progressively declining into the 55 to 60 percent range on repeat imaging. The 2025 European guidelines introduced a recommendation for early surgery in select low-risk patients whose measurements are creeping toward those thresholds. The goal in all cases is the same: fix the valve before irreversible heart muscle damage sets in.
Surgical Options
The standard treatment for severe aortic regurgitation is surgery, and there are three main approaches.
- Mechanical valve replacement uses a durable artificial valve made of metal and carbon. These valves last a very long time, but they require lifelong blood-thinning medication, which increases the risk of bleeding events.
- Biological (bioprosthetic) valve replacement uses a valve made from animal tissue. Blood thinners are typically only needed short-term, but these valves wear out over time and may eventually need a second operation.
- Aortic valve repair preserves and reshapes the patient’s own valve. This avoids the need for blood thinners and carries a lower risk of clot-related complications. It’s particularly useful for children, whose growing hearts make replacement valves impractical. The challenge is that repair is technically demanding due to the complex anatomy of the aortic valve, which is one reason it hasn’t become as widespread as repair of other heart valves.
The choice between these options depends on age, lifestyle, anatomy, and the specific cause of the regurgitation. Younger patients often face the hardest trade-off: a mechanical valve that lasts but requires lifelong medication, or a biological valve that avoids blood thinners but may need replacing in 10 to 20 years. Valve repair, when feasible, increasingly offers a middle path that sidesteps both drawbacks.
Living With Aortic Regurgitation
Mild to moderate aortic regurgitation often requires nothing more than regular monitoring with periodic echocardiograms to track the size and function of the left ventricle. Many people live normal, active lives for years without needing any intervention. The key is consistent follow-up so that changes in heart size or function are caught early, well before symptoms develop or irreversible damage occurs.
For those with more significant leakage, staying aware of new or worsening symptoms, particularly shortness of breath during activities that were previously easy, unusual fatigue, or a pounding sensation in the chest, helps ensure timely evaluation. Controlling blood pressure reduces the extra stress on the valve and the left ventricle, which can slow progression in some cases.