Congenital heart defects are structural problems with the heart that are present at birth. These defects can affect the heart's walls, valves, or blood vessels, leading to issues with blood flow. Some common types include ventricular septal defects, where there is a hole between the heart's chambers, and tetralogy of Fallot, which involves four different heart defects. The exact cause of congenital heart defects is often unknown, but they can result from genetic factors or environmental influences during pregnancy. Symptoms may vary, with some infants showing no signs, while others may experience difficulty breathing or poor weight gain. Early diagnosis and treatment are essential for managing these conditions.