Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for a baby or child who suddenly becomes much bluer or grayer than usual, has severe breathing difficulty, faints, has a seizure, becomes limp, or is difficult to wake.
A suspected tet spell is an emergency, particularly if the color change or breathing problem is severe or does not settle quickly.
While waiting for help, keep the child calm.
If previously taught to do so, gently bring an infant's knees toward the chest.
Do not delay emergency care to try home measures.
Emergency assessment is also needed for severe chest pain, collapse, or a sustained fast or irregular heartbeat accompanied by breathlessness, weakness, or fainting.
Seek prompt medical advice for new or increasing cyanosis, faster breathing, feeding difficulty, poor weight gain, reduced activity, swelling, repeated palpitations, or a clear decline in exercise ability.
Routine follow-up is different from urgent care.
Keep planned congenital heart appointments even when you or your child feels well.
Contact the heart team routinely if an appointment has been missed, activity advice is unclear, or dental, travel, school, work, or pregnancy planning needs to be discussed.
Every sign above is quoted from the sofidex article on Tetralogy of fallot. If you are not sure, err upward — it is always reasonable to be checked.