In newborn babies, even a large hole may cause no problems until circulation has adjusted fully to being out of the womb - a period of about a month. The diagnosis of the condition - Ventricular Septal Defect, is usually made (except in the first week or two after birth) by examining the child and hearing a heart murmur due to the blood passing through the hole.
Larger holes allow enough blood to pass into the lungs to cause breathlessness, poor weight gain and an increased susceptibility to infections.
Breathlessness can occur in small babies - particularly when they feed. It occurs in some heart conditions for example a hole in the heart or if there is a leaky heart valve. Worrying signs are if the skin is sucked in between the ribs or below the lower border of the ribs (recession).
Lung problems can also cause breathing problems and so the advice of a doctor is essential.
Breathlessness on running or other exercise is normal unless it is out of proportion to the exercise taken - as a general rule children should be able to manage as well as their friends.
Blue colouration is common in babies and young children. It is usually confined to the area around the mouth ("muzzle area") and the hands and feet. The colour change usually occurs for no apparent reason and the child is completely well. The technical term for these colour changes is acrocyanosis. It is probably caused by local variation in blood flow through the skin - as oxygen is extracted from the blood by the tissues it changes to a blue colour. It is of no consequence and usually goes away as the child gets older.
Blue colour (cyanosis) can be a sign of heart disease and in others they develop - either as a result of untreated heart disease, in this case, a large Ventricular Septal Defect.