If your heart and its chambers weren't formed correctly before you were born, the blood flow in your heart or vessels near it may be blocked or have abnormal pathways or connections. This may cause the oxygen-rich blood from your lungs to mix with blood from your body that is low in oxygen. When this happens cyanosis occurs and your body could potentially lack the right levels of oxygen to sustain itself. This makes it harder for your heart to pump blood around your body and the extra workload can cause many conditions, including heart failure.
For more information on congenital heart defects, visit the websites below: