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 help for possible signs of a heart attack, including:
New chest pressure, tightness, squeezing, or pain that does not settle
Discomfort spreading to an arm, shoulder, jaw, back, or upper abdomen
Chest discomfort with sweating, nausea, breathlessness, or faintness
Call emergency services for possible stroke signs, such as sudden facial drooping, weakness or numbness on one side, trouble speaking, loss of vision, severe imbalance, or an unusual sudden headache.
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
Does any of this apply?
Book an appointment
Arrange a routine appointment if you have repeatedly high LDL, a close relative with FH, or a family pattern of heart attacks or coronary procedures at young ages.
Swellings over the Achilles or hand tendons also need assessment.
The article also says
If you have FH, contact your healthcare team if you develop possible medicine side effects, have difficulty taking treatment consistently, become pregnant, or plan a pregnancy.
Do not drive yourself if you may be having a heart attack or stroke.
Every sign above is quoted from the sofidex article on Familial hypercholesterolemia. If you are not sure, err upward — it is always reasonable to be checked.