Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Seek emergency medical help for:
Severe trouble breathing
Blue or gray lips, tongue, or skin that does not quickly improve
Collapse, fainting, or difficulty waking
New severe chest pain
A very fast or irregular heartbeat with faintness or breathing difficulty
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Contact the heart team promptly if a baby is feeding much less than usual, sweating heavily during feeds, breathing faster over several hours, producing fewer wet diapers, or becoming unusually sleepy.
3
Does any of this apply?
Book an appointment
Arrange medical review for gradual changes such as reduced stamina, slower weight gain, new swelling, increasing breathlessness with activity, or frequent racing or irregular heartbeats.
The article also says
Color changes may be harder to see on darker skin.
Check the lips, tongue, gums, palms, and soles, and pay attention to breathing and alertness.
Every sign above is quoted from the sofidex article on Endocardial cushion defect. If you are not sure, err upward — it is always reasonable to be checked.