What Is a Heart Attack?
A heart attack (myocardial infarction) occurs when a coronary artery is suddenly blocked — usually by a ruptured atherosclerotic plaque — cutting off blood supply to part of the heart muscle. Every minute without blood flow causes more permanent damage.
Call 999/911 Immediately If You Have:Chest pain or pressure lasting more than 15 minutes | Pain spreading to arm, jaw, neck or back | Shortness of breath | Nausea, cold sweats or dizziness with chest discomfort.
Types of Heart Attack
| Type | ECG Finding | Treatment Priority |
|---|---|---|
| STEMI | ST elevation — full blockage | Emergency angioplasty (PCI) within 90 minutes |
| NSTEMI | No ST elevation — partial blockage | Urgent but slightly more time — medications first, then PCI |
| Unstable angina | No troponin rise | Urgent investigation and treatment — high risk |
Blood Tests Used to Diagnose Heart Attack
| Test | Timing | Purpose |
|---|---|---|
| Troponin I or T (high-sensitivity) | 0 hr and 3 hr (or 0 and 1 hr for hs-Troponin) | Gold standard — confirms muscle damage |
| ECG | Immediately | Identifies STEMI — guides urgency |
| Full Blood Count | On arrival | Anaemia, platelet count |
| BNP | At presentation | Heart failure severity |
| Kidney function | On arrival | Baseline before contrast dye for angiogram |
| Glucose + HbA1c | On arrival | Diabetes assessment |
| Lipid profile | Within 24 hours | Statin prescribing decision |
FAQs
Can a heart attack happen with no chest pain?
Yes — especially in women, diabetics and older adults. Back pain, jaw pain, breathlessness, fatigue or nausea can be the only symptoms. These are 'silent' heart attacks.
How long does troponin stay elevated?
Troponin peaks at 12–24 hours and stays elevated for 7–14 days — useful for diagnosing recent heart attacks.
What is a normal troponin?
Laboratory-dependent. High-sensitivity troponin normal is typically below 14–52 ng/L depending on the assay. A rise and fall pattern confirms acute injury.
Medical Disclaimer: Heart attack is a life-threatening emergency requiring immediate medical treatment. Do not delay calling emergency services.