Ventricular aneurysms are usually after effects of myocardial infarctions. When the heart muscle (cardiac muscle) partially dies during a heart attack, a layer of muscle may survive, and being severely weakened, start to become an aneurysm. The blood may flow into the surrounding dead muscle and inflate the weakened flap of muscle into a bubble.

Signs and symptoms
Ventricular aneurysms usually grow at a very slow pace, but can still pose problems. Usually this type of aneurysm grows in the left ventricle. This bubble has the potential to block blood flow to the body, and thus limit the patient's stamina. In other cases, a similarly developed pseudoaneurysm "false aneurysm" may burst, sometimes resulting in death of the patient. Also, blood clots may form on the inside of ventricular aneurysms, and form embolisms. If these blood clots escape from the aneurysm, they will be moved in the circulation throughout the body. If these blood clots get stuck inside a blood vessel, they may cause ischemia in a limb, a painful condition that can lead to reduced movement and tissue death in the limb. Alternatively, if they block a vessel going to the brain, they can cause a stroke. In certain cases, ventricular aneurysm may cause ventricular failure or arrythmia. At this stage, treatment is necessary.

The ratio of the maximum diameter of the orifice to the maximum internal diameter of the cavity may higher (0.9-1.0) than for a pseudoaneurysm