Complications

Congenital heart disease complications that might develop years after the initial treatment include:

• Abnormal heart rhythms (arrhythmias). Arrhythmias occur when the electrical impulses that coordinate heartbeats don't function properly, causing your heart to beat too fast, too slowly or irregularly. In some people, severe arrhythmias can cause sudden cardiac death if not treated.

• Heart infection (endocarditis). Your heart comprises four chambers and four valves, which are lined by a thin membrane called the endocardium. Endocarditis is an infection of this inner lining, which generally occurs when bacteria or other germs enter your bloodstream and lodge in your heart. Untreated, endocarditis can damage or destroy your heart valves or trigger a stroke.

  If you have an artificial (prosthetic) heart valve or your heart was repaired with prosthetic material, or if your heart defect wasn't completely repaired, your doctor might prescribe ongoing antibiotics to lower your risk of developing endocarditis.

• Stroke. Stroke occurs when the blood supply to a part of your brain is interrupted or severely reduced, depriving brain tissue of oxygen. A congenital heart defect can allow a blood clot to pass through your heart and travel to your brain.

  Certain heart arrhythmias also can increase your chance of blood clot formation leading to a stroke.

• Heart failure. Heart failure, also known as congestive heart failure, means your heart can't pump enough blood to meet your body's needs. Some types of congenital heart disease can lead to heart failure.

  Over time, certain conditions such as coronary artery disease or high blood pressure gradually sap your heart of its strength, leaving it too weak or too stiff to fill and pump efficiently.

• Pulmonary hypertension. This is a type of high blood pressure that affects the arteries in your lungs. Some congenital heart defects cause more blood to flow to the lungs, causing pressure to build and making your heart work harder. This eventually causes your heart muscle to weaken and sometimes to fail.
• Heart valve problems. In some types of congenital heart disease, the heart valves are abnormal.