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
Call emergency services for:
Severe or persistent chest pain
Severe difficulty breathing
Fainting with chest pain, palpitations, or exercise
A fast or irregular heartbeat with marked weakness or breathlessness
Signs of stroke, such as facial drooping, arm weakness, or speech difficulty
Collapse, unresponsiveness, or absent normal breathing
If someone collapses and is not breathing normally, call emergency services, begin CPR if able, and use an automated external defibrillator if one is available.
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 your cardiology team promptly after an unexplained fainting episode, particularly if it happened during exercise.
New sustained palpitations or a newly irregular pulse also need timely assessment.
3
Does any of this apply?
Book an appointment
Arrange a routine medical review if you develop new mild breathlessness, reduced exercise tolerance, recurring palpitations, ankle swelling, or chest discomfort.
Also seek review if established symptoms are becoming more frequent or medicines are causing problems.
Every sign above is quoted from the sofidex article on Hypertrophic cardiomyopathy. If you are not sure, err upward — it is always reasonable to be checked.