Chest pain, sweating, short of breath
A blocked artery is starving the heart of oxygen. Minutes matter. The goal is to get them to a hospital quickly and keep them calm in the meantime.
Don't drive them yourself if an ambulance is available — paramedics start treatment on the way.
Half-sitting position with knees bent (W-position) takes pressure off the heart. Loosen tight clothing.
Reassure them. No walking, no climbing stairs. Movement increases heart workload.
Have them chew (not swallow whole) one regular aspirin (300 mg). Ask first if they can take aspirin.
If they stop responding or stop breathing normally, start CPR. An AED, if available, can save them.
Some people deny they're having a heart attack. If you suspect it, call 108. Better a false alarm than a death.
These are short summaries, not training. Always call 108 in a life-threatening situation. If you've been trained in first-aid, follow your training.