Acyanotic heart disease is where the blood contains enough oxygen but it's pumped abnormally around the body. Babies born with acyanotic heart disease may not have any apparent symptoms but, over time, the condition can cause health problems. In this group of conditions there can be a significant increase in blood pressure, putting the heart under more strain as it works much harder. This can weaken the heart, and increases the risk of developing heart failure, where the muscle is unable to efficiently pump blood around the body. In addition, the blood pressure in the lungs is often too high. This is known as pulmonary hypertension and can damage the lungs and cause symptoms such as: breathlessness fatigue dizziness fainting