A hole in your heart means there’s an opening in the wall (septum) that separates the heart’s chambers, allowing blood to leak between sides that should be completely sealed off from each other. Many people live for years without knowing they have one. Some holes are small enough to close on their own or never cause problems. Others gradually strain the heart and lungs, and if left untreated, can lead to serious complications like heart failure, irregular heart rhythms, or stroke.
Where the Hole Can Be
Your heart has four chambers: two upper (atria) and two lower (ventricles). A hole can form in the wall between either pair. An atrial septal defect (ASD) is a hole between the upper chambers, and it’s the most common type, making up about 25% of all congenital heart defect diagnoses. A ventricular septal defect (VSD) is a hole between the lower chambers, accounting for roughly 11% of diagnoses.
There’s also a third, very common variation called a patent foramen ovale, or PFO. Every baby has a small flap-like opening between the upper chambers before birth, which normally seals shut in the first weeks of life. In about 1 in 4 people, it never fully closes. A PFO is usually harmless, but it can become significant under certain circumstances, particularly when it comes to stroke risk.
How Blood Flow Changes
In a healthy heart, oxygenated and deoxygenated blood stay completely separate. The right side pumps blood to the lungs to pick up oxygen, and the left side pumps that freshly oxygenated blood out to the body. The two circuits run in parallel, each feeding the other in a balanced one-to-one volume relationship.
A hole disrupts that balance. Because the left side of the heart operates at higher pressure, blood typically leaks from left to right, sending already-oxygenated blood back toward the lungs instead of out to the body. This is called a left-to-right shunt. It means the lungs receive more blood than they should, while the rest of the body gets less than it needs. The larger the hole, the more blood takes this wrong turn, and the harder the heart and lungs have to work to compensate.
In some cases the shunt can reverse direction, pushing deoxygenated blood from the right side into the left side and out to the body without ever passing through the lungs. This right-to-left shunt is more dangerous because it lowers oxygen levels in the blood reaching your brain, organs, and tissues.
Symptoms You Might Notice
Many people with small holes have no symptoms at all. A baby born with an ASD may seem perfectly healthy, with symptoms only appearing later in adulthood as the heart gradually becomes overworked. When symptoms do develop, they tend to include:
- Shortness of breath, especially during exercise
- Fatigue that worsens with physical activity
- Swelling in the legs, feet, or abdomen
- Irregular heartbeats or a fluttering, pounding sensation in the chest
- Skipped heartbeats
These symptoms are easy to dismiss as being out of shape or getting older, which is one reason ASDs in adults often go undiagnosed for decades. A heart murmur, an unusual sound a doctor hears through a stethoscope, is frequently the first clue.
What Happens If It’s Not Treated
A small hole that causes minimal extra blood flow may never need treatment. But a larger, uncorrected hole forces the right side of the heart and the lungs to handle a chronic volume overload. Over time, the extra blood flow damages the small blood vessels in the lungs. The vessel walls thicken and stiffen, a condition called pulmonary hypertension. As pressure in the lungs climbs, the right side of the heart has to pump harder, which can eventually weaken it and lead to heart failure.
The most severe outcome of an untreated large hole is Eisenmenger syndrome. This happens when lung pressure rises so high that it exceeds the pressure on the left side of the heart, permanently reversing the shunt direction. Deoxygenated blood then flows into the body, causing chronically low oxygen levels, blue-tinged skin, and progressive organ damage. Once Eisenmenger syndrome develops, closing the hole is no longer safe because the lungs can no longer handle normal blood flow. This is why early detection matters so much.
Arrhythmias are another common consequence. The extra volume stretching the heart chambers over years disrupts the electrical signaling that keeps the heart beating in rhythm. Atrial fibrillation and other irregular rhythms become increasingly likely the longer a significant defect goes unrepaired.
The Link Between Heart Holes and Stroke
A PFO deserves special attention because of its connection to stroke. Normally, if a small blood clot forms in a vein (say, in your leg), it travels to the lungs, where the tiny blood vessels filter it out before it can cause harm. But with a PFO, that clot can slip through the opening directly into the left side of the heart and travel straight to the brain, causing what’s called a paradoxical stroke.
This link is strongest in younger stroke patients. Among young adults who have a stroke with no identifiable cause (cryptogenic stroke), 40% to 50% are found to have a PFO, compared to just 10% to 15% in the general population. Analysis suggests a PFO may be the actual cause in roughly two-thirds of these unexplained strokes, and up to 80% in younger patients. For someone who has already had a cryptogenic stroke and is found to have a PFO, closing it can significantly reduce the chance of a second stroke.
How Heart Holes Are Repaired
Doctors weigh several factors when deciding whether a hole needs to be closed: how much extra blood is flowing through it, whether it’s causing symptoms, and whether lung pressure is rising. For ASDs, current guidelines recommend considering closure when the extra blood flowing through the lungs is at least 1.5 times the normal amount, or when pulmonary pressure starts climbing toward concerning levels.
The least invasive option is a catheter-based procedure. A cardiologist threads a thin, flexible tube through a blood vessel in the groin, guiding it up to the heart using X-ray and ultrasound imaging. A small closure device, folded up like an umbrella inside the catheter, is pushed out and positioned across the hole, plugging it from both sides. Over the following weeks, the body’s own tissue grows over the device, permanently sealing it in place. This approach works best for the most common type of ASD, the secundum defect, which sits in the middle of the wall between the upper chambers.
Holes in other locations, very large defects, or VSDs that need repair typically require open-heart surgery. The surgeon patches the hole with synthetic material or the patient’s own tissue. This is a bigger procedure, but outcomes are generally excellent when done before significant lung damage has occurred.
What Recovery Looks Like
After a catheter-based closure, most people stay in the hospital for one night and return to normal activity within about a week. Surgical closure requires a longer hospital stay and several weeks of limited physical activity while the chest heals. In both cases, follow-up appointments with a cardiologist are important in the months and years afterward to confirm the repair is holding and the heart is functioning well.
For people whose holes are caught and repaired before complications set in, the long-term outlook is excellent. The heart gradually adjusts to its corrected blood flow, symptoms like fatigue and breathlessness improve, and the risk of developing pulmonary hypertension or heart failure drops dramatically. People who had repairs as children often live completely normal lives with no ongoing restrictions.