A ventricular aneurysm is a bulge or outpouching in the weakened wall of the heart’s ventricle, almost always the left ventricle. It typically forms after a heart attack damages a section of heart muscle so severely that the tissue dies and is replaced by scar tissue, creating a thin, non-contractile pocket that balloons outward each time the heart beats. Roughly 5% to 16% of people who survive a heart attack develop one, with some studies reporting rates as high as 15.9% after a major anterior heart attack.
How a Ventricular Aneurysm Forms
The process starts with a full-thickness heart attack, meaning the damage extends through the entire wall of the heart muscle rather than just part of it. Within hours, the affected zone begins to thin dramatically. Over the following days and weeks, the dead muscle cells are gradually replaced by stiff fibrous scar tissue.
Because scar tissue cannot contract, it becomes a dead zone in the heart wall. When the rest of the ventricle squeezes during each heartbeat (systole), the scarred patch bulges outward instead of contracting inward. This creates a permanent, thin-walled pouch. About half of ventricular aneurysms form within two days of a heart attack, and most of the rest appear within two weeks.
True Aneurysm vs. Pseudoaneurysm
There are two distinct types, and the difference matters because one is far more dangerous than the other.
A true ventricular aneurysm still contains all three layers of the heart wall, though the muscle layer is severely thinned and replaced by scar. It has a wide opening, or “neck,” that is roughly the same width as the bulging pouch itself. True aneurysms carry a relatively low risk of rupture and can often be managed without surgery.
A pseudoaneurysm (false aneurysm) is a different situation entirely. It forms when the heart wall actually ruptures, but the tear is contained by the surrounding pericardium (the sac around the heart) or scar tissue rather than the heart muscle itself. The wall of a pseudoaneurysm lacks the heart’s own muscle and lining layers. It connects to the ventricle through a narrow neck, typically less than half the width of the bulging sac. Untreated pseudoaneurysms carry a 30% to 45% chance of rupture, making them a surgical emergency in most cases.
Symptoms and Warning Signs
Many ventricular aneurysms cause no obvious symptoms at first and are discovered during follow-up imaging after a heart attack. When symptoms do appear, they generally fall into three categories.
The most common is heart failure. Because the aneurysm creates a section of wall that bulges outward instead of pumping, the heart becomes less efficient. Over time, this can lead to shortness of breath, fatigue, swelling in the legs or ankles, and difficulty lying flat to sleep. The larger the aneurysm, the more pumping ability is lost.
Abnormal heart rhythms are another concern. The border zone between healthy muscle and scar tissue can generate erratic electrical signals, leading to palpitations, dizziness, or in serious cases, dangerous arrhythmias that cause fainting or cardiac arrest.
The third category involves blood clots. Blood can pool and swirl inside the still pouch of the aneurysm, encouraging clot formation. If a clot breaks loose, it can travel to the brain and cause a stroke, or block blood flow to other organs.
Blood Clot and Stroke Risk
Blood clots forming inside a ventricular aneurysm are a well-documented risk. Historically, clots formed in 20% to 40% of post-heart attack patients, and rates reached as high as 60% in people with large anterior heart attacks. Modern treatment has brought those numbers down substantially. Among patients treated with current catheter-based procedures to reopen blocked arteries, the clot rate has dropped to roughly 2.7%.
When clots do form, the risk of them traveling elsewhere in the body is highest in the first three months. The median time from clot detection to a stroke is about 20.5 days. Among patients who suffer a stroke related to a heart clot, roughly three-quarters are caused by a piece of the clot breaking off and lodging in the brain. Even after a clot appears to resolve on imaging, about 5% of patients still go on to have a stroke, which is why ongoing monitoring and blood-thinning medication remain important.
How It Is Diagnosed
The first clue often comes from an electrocardiogram (ECG). Persistent ST elevation, a pattern on the heart tracing that typically signals an active heart attack, can linger for weeks or months after a heart attack in patients who develop a ventricular aneurysm. Persistent T-wave inversions in the same leads are another red flag. These findings are not always present, though, so imaging is needed to confirm the diagnosis.
Echocardiography (ultrasound of the heart) is the most common imaging tool. It can show a section of the ventricular wall that is either completely still (akinetic) or bulging outward during contraction (dyskinetic). The shape of the opening helps distinguish a true aneurysm from a pseudoaneurysm: in a true aneurysm, the neck is as wide as or wider than the pouch, while in a pseudoaneurysm, the neck is noticeably narrower, typically half the width of the sac or less. Additional imaging with cardiac MRI or CT may be used for a more detailed view, especially when planning treatment.
Treatment and Management
Small, stable ventricular aneurysms that are not causing significant symptoms can often be managed with medications. The goals are to reduce the workload on the heart, prevent further enlargement, and lower the risk of blood clots. This typically involves medications that lower blood pressure and reduce the strain on the ventricle, along with blood thinners to prevent clot formation inside the aneurysm.
Surgery becomes an option when the aneurysm is large enough to significantly impair heart function, when dangerous arrhythmias cannot be controlled with medication, or when blood clots keep forming despite blood thinners. The most well-known surgical approach is the Dor procedure, in which the surgeon opens the aneurysm, removes the scar tissue and any clot, and then places a patch inside the ventricle to restore a more normal chamber shape and size. An older, simpler technique involves cutting out the scarred section and sewing the edges together in a straight line (linear repair).
Long-term survival after surgical repair is encouraging. Five-year survival rates are approximately 91%, dropping to about 81% at ten years and 74% at fifteen years. Patch-based repairs show a slight edge over linear repairs, with ten-year survival around 85% compared to 80%.
Living With a Ventricular Aneurysm
For many people, a ventricular aneurysm is a chronic condition managed alongside their broader post-heart attack care. Regular follow-up imaging tracks the size of the aneurysm and monitors heart function over time. Blood-thinning medications may be prescribed for months or indefinitely depending on clot risk. Controlling blood pressure is particularly important, since higher pressure puts more stress on the weakened wall with every heartbeat.
The outlook depends heavily on the size of the aneurysm, how much pumping function the heart retains, and whether complications like clots or arrhythmias develop. People with small aneurysms and preserved heart function generally do well with medical management alone, while those with larger aneurysms or worsening symptoms may eventually need surgical repair to improve quality of life and long-term survival.