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 now if you or someone else has a rapid heartbeat together with:
Fainting or near-fainting
Chest pain or pressure
Severe shortness of breath
Confusion, marked weakness, or difficulty staying awake
Collapse or unresponsiveness
If someone is unresponsive and not breathing normally, call emergency services, begin CPR if you can, and use an automated external defibrillator if one is available.
If you have an ICD, seek emergency help after a shock if you still feel unwell, have chest pain or breathlessness, faint, or receive more than one shock.
Follow the individual emergency plan provided by your device clinic.
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
Arrange prompt medical assessment for new episodes of a racing heartbeat, unexplained fainting, or repeated dizziness, even if the symptoms have stopped.
3
Does any of this apply?
Book an appointment
Routine cardiology follow-up remains important when VT has already been diagnosed, including after symptom-free periods.
Every sign above is quoted from the sofidex article on Ventricular tachycardia. If you are not sure, err upward — it is always reasonable to be checked.