How is a heart attack diagnosed in hospital?

Diagnosis uses two key tools: an ECG (electrocardiogram), which records the heart's electrical activity and can show whether a major artery is blocked, and blood tests for troponin, a protein released by damaged heart muscle. Together, these tests usually confirm or rule out a heart attack within 1–3 hours. Repeat troponin tests over several hours improve accuracy.

What is a stent and how does it work?

A stent is a small metal mesh tube inserted into a blocked coronary artery to hold it open. During primary PCI (angioplasty), a cardiologist threads a thin tube through an artery in the wrist or groin to the blockage, inflates a tiny balloon to open the artery, and places the stent. Most stents today are drug-eluting — they release medication over time to prevent re-narrowing.

When can I return to normal activities after a heart attack?

Most people with an uncomplicated MI and stent placement can return to light activities within 1–2 weeks and resume most normal activities within 4–6 weeks. Return to work, driving, and sexual activity depend on the procedure, your job, and clinical recovery. Cardiac rehabilitation provides a structured, supervised path back to activity — it significantly reduces the risk of a second heart attack.

What is CABG (bypass surgery) and when is it used?

Coronary artery bypass grafting (CABG) uses a blood vessel from elsewhere in the body (often the chest or leg) to reroute blood flow around a blocked coronary artery. It is used when the blockage is too complex for a stent, when multiple arteries are severely diseased, or in certain high-risk anatomical patterns. It is open-heart surgery and requires several weeks of recovery, but provides excellent long-term outcomes for appropriate patients.

Heart Attack Treatment — Emergency Care, Procedures, and Recovery

Intro

A heart attack is a medical emergency. How quickly treatment begins, and what that treatment involves, makes a substantial difference to the amount of heart muscle saved — and to long-term outcomes.

This guide explains what happens when a heart attack is treated: the emergency response in the first minutes, what paramedics and hospital teams do, the procedures used to restore blood flow, and what recovery and long-term care involve.

It is not a guide for self-diagnosing. If you or someone near you may be having a heart attack, call emergency services immediately. Do not consult a guide first.

Key Points

Call emergency services immediately if heart attack is suspected — do not drive yourself to hospital; paramedics can begin treatment on the way
The critical goal is restoring blood flow to the blocked coronary artery as quickly as possible — every minute of delay costs heart muscle
Primary PCI (angioplasty with stent) is the preferred treatment when available within the time window — faster and more effective than clot-busting drugs at most hospitals
Thrombolysis (clot-dissolving drugs) is used when primary PCI is not available within the recommended time window
CABG (bypass surgery) is used for complex multi-vessel disease or when anatomy is not suitable for stenting
After the acute event, long-term prevention is essential: medications, cardiac rehabilitation, and risk factor management all reduce the risk of a second event

What Is a Heart Attack?

A heart attack (myocardial infarction or MI) occurs when a coronary artery — one of the vessels supplying blood to the heart muscle — becomes blocked, cutting off oxygen supply to part of the heart.

The blockage is almost always caused by a blood clot forming on a ruptured atherosclerotic plaque: a fatty deposit in the artery wall that has accumulated over years. When the plaque ruptures, the body treats it like a wound and forms a clot — but that clot can completely block the artery.

Without blood flow, heart muscle begins to die within minutes. The amount of damage depends on which artery is blocked, how completely it is blocked, and how long before blood flow is restored.

There are two main types:

STEMI (ST-elevation myocardial infarction) — a complete blockage of a major coronary artery, visible on the ECG as ST elevation; requires the fastest possible treatment
NSTEMI (non-ST-elevation MI) — a partial blockage or smaller area of damage; treated urgently but with a slightly different pathway; diagnosed primarily through troponin testing

Emergency Response — The First Minutes Matter

What to Do

If you or someone else may be having a heart attack:

Call emergency services immediately — 999 (UK), 911 (US), 112 (Europe), or your local emergency number
Do not drive to hospital — paramedics can begin assessment and treatment on the way; driving yourself delays care and puts others at risk
Sit or lie down in a comfortable position — usually sitting upright with knees bent
Chew one aspirin 300 mg if available and the person is not allergic to aspirin and has not been told not to take it — chewing gets it into the bloodstream faster than swallowing whole
Unlock the front door if alone so paramedics can enter
Stay on the line with the emergency dispatcher — they will guide you until help arrives

Do not wait to see if symptoms pass. Heart attacks can present with chest pain, but also with breathlessness, jaw or arm pain, sweating, nausea, or a feeling of impending doom. Atypical presentations are particularly common in women and people with diabetes. When in doubt, call.

See Chest Pain — When to Worry and What to Do for a full overview of warning symptoms.

”Time Is Muscle”

Every minute a coronary artery is blocked, approximately 2 million heart muscle cells die. This is why emergency systems worldwide measure performance against strict time targets:

Door-to-balloon time — the time from hospital arrival to when the blocked artery is opened by PCI — target: under 60–90 minutes
The earlier treatment begins, the more heart muscle is saved, and the better the long-term outcome

In Hospital — Diagnosis

ECG (Electrocardiogram)

The ECG is performed within minutes of arrival. It records the electrical activity of the heart and can reveal the characteristic pattern of a STEMI (ST elevation) immediately, triggering the fastest possible response — the cardiac catheterisation lab is activated while the patient is still being assessed.

A normal ECG does not rule out a heart attack (NSTEMI may show only subtle changes).

Troponin Blood Tests

Troponin is a protein released into the bloodstream when heart muscle is damaged. In a heart attack, troponin levels rise within 2–4 hours and remain elevated for several days. A single normal troponin on arrival does not rule out MI — a second test 1–3 hours later is used in most protocols.

High-sensitivity troponin assays allow faster rule-in or rule-out of MI, reducing the time patients wait in emergency departments.

Imaging

Echocardiography (ultrasound of the heart) may be performed to assess how well the heart is pumping and whether there are areas of wall motion abnormality consistent with MI.

Restoring Blood Flow — The Core Treatment

Primary PCI (Angioplasty with Stent)

Primary PCI (percutaneous coronary intervention) is the preferred treatment for STEMI — and for many NSTEMIs — when it can be performed within the recommended time window.

How it works:

A cardiologist threads a thin, flexible tube (catheter) through an artery in the wrist (radial artery — most common today) or groin (femoral artery)
A wire is guided to the blocked coronary artery under X-ray imaging
A small balloon is inflated at the blockage to open the artery
A stent — a metal mesh tube — is placed to keep the artery open
Most stents are drug-eluting: they release medication over time to prevent the artery from re-narrowing (restenosis)

Primary PCI is performed in a cardiac catheterisation laboratory (“cath lab”). The procedure typically takes 30–60 minutes. Most patients are awake throughout under local anaesthetic with sedation available.

After PCI: Most patients with an uncomplicated MI can sit up and eat within hours. Radial access (wrist) allows earlier mobilisation than femoral access (groin).

Thrombolysis (Clot-Busting Drugs)

Thrombolysis uses intravenous drugs (such as alteplase, tenecteplase, or streptokinase) to dissolve the blood clot in the coronary artery.

It is used when:

Primary PCI is not available within the recommended window (typically >120 minutes from first medical contact)
The patient presents very early and the PCI lab is further away

Thrombolysis works best when given within 2–3 hours of symptom onset and is significantly less effective after 6 hours. It is effective in opening arteries but slightly less reliable and carries a small risk of serious bleeding, including haemorrhagic stroke (approximately 1%).

After successful thrombolysis, patients are often transferred for coronary angiography within 3–24 hours to assess whether a stent is also needed.

Coronary Artery Bypass Grafting (CABG)

CABG uses blood vessels from elsewhere in the body (usually the internal mammary artery from the chest, or the saphenous vein from the leg) to bypass blocked coronary arteries and restore blood flow.

CABG is used when:

The coronary anatomy is not suitable for stenting (e.g. left main artery disease, complex three-vessel disease)
The blockage cannot be crossed with a catheter
A previous stent has failed and re-stenting is not appropriate

CABG requires open-chest surgery under general anaesthetic, usually taking 3–6 hours. Recovery involves 5–7 days in hospital and 6–12 weeks of recuperation at home. Long-term results are excellent for appropriate patients.

ICU and Cardiac Monitoring

After primary PCI or thrombolysis, patients are monitored on a coronary care unit (CCU) or high-dependency unit for 24–48 hours or longer if there are complications.

Monitoring includes:

Continuous ECG monitoring for arrhythmias
Repeat echocardiography to assess heart function
Blood pressure, oxygen saturation, and fluid balance
Daily troponin and other blood tests

After an uncomplicated STEMI treated with PCI, many patients are transferred to a general cardiology ward within 24 hours.

Medications After a Heart Attack

Almost everyone discharged after a heart attack leaves on a combination of medications. These work together to prevent clot formation, stabilise plaques, protect heart function, and lower future risk:

Medication	Purpose
Aspirin	Antiplatelet — reduces clot formation; usually lifelong
P2Y12 inhibitor (ticagrelor, clopidogrel, prasugrel)	Second antiplatelet — combined with aspirin for 6–12 months after stent (dual antiplatelet therapy)
Statin (atorvastatin 80 mg typical)	Lowers LDL cholesterol and stabilises plaques; lifelong
ACE inhibitor or ARB (e.g. ramipril, candesartan)	Reduces blood pressure, protects heart function, especially if ejection fraction is reduced
Beta-blocker (e.g. bisoprolol, metoprolol)	Slows heart rate, reduces blood pressure, protects against arrhythmia

Some patients also receive:

Eplerenone (aldosterone antagonist) if there is significant left ventricular dysfunction
SGLT2 inhibitors (e.g. dapagliflozin) if heart failure is present
Nitrates for ongoing angina symptoms
Anticoagulants if atrial fibrillation is present

Medication adherence is critical. Stopping antiplatelet therapy early after stent placement significantly increases the risk of stent thrombosis — a very dangerous complication. Do not stop or reduce any cardiac medication without consulting your cardiologist.

See Common Heart Medications and Their Side Effects for detailed guidance on each drug class.

Recovery After a Heart Attack

In the First Weeks

Rest, then gradual return to activity — most people can manage light household tasks within 1–2 weeks; heavy lifting and strenuous exertion is restricted longer
Wound care (if wrist or groin access used for PCI) — follow nursing discharge instructions; report any bleeding, swelling, or spreading redness
Follow-up appointments — typically within 1–2 weeks with your GP and 6–8 weeks with cardiology; arrange these before leaving hospital

Driving

UK rules: Do not drive for at least 1 week after an uncomplicated MI and PCI (Group 1 licence); Group 2 (HGV/bus) licences have stricter rules and require DVLA notification
After CABG, guidance varies but is typically 4–6 weeks minimum
Your discharge letter will specify your restriction

Returning to Work

Most desk-based workers return within 2–6 weeks
Physically demanding jobs may require 6–12 weeks or a phased return
Discuss with your GP and occupational health team if needed

Sexual Activity

Generally safe once you can climb two flights of stairs without symptoms — usually within 2–4 weeks after an uncomplicated MI
Erectile dysfunction after MI is common and treatable; speak with your GP
Note that some medications used in heart disease (nitrates) interact with PDE5 inhibitors (sildenafil/Viagra) — never take both together

Cardiac Rehabilitation

Cardiac rehabilitation is the single most important thing you can do to accelerate recovery and reduce the risk of a second heart attack. Evidence shows it reduces mortality by approximately 20–25% compared with usual care. It should be offered to every patient after MI — if you haven’t been referred, ask for it.

See Cardiac Rehabilitation — What It Is and Why It Matters.

Complications to Know About

Most heart attacks treated promptly have good outcomes, but complications can occur:

Arrhythmias — abnormal heart rhythms are common in the first 24–48 hours; ventricular fibrillation (VF) can be fatal but is treatable in a monitored setting; some patients require a pacemaker or defibrillator implant
Heart failure — if a large area of heart muscle is damaged, the heart may pump less effectively; treated with medications (ACE inhibitors, beta-blockers, diuretics) and sometimes devices
Cardiogenic shock — severe pump failure requiring intensive support; relatively rare after successful PCI
Pericarditis — inflammation of the heart lining, causing chest pain 1–7 days after MI (Dressler syndrome); usually treated with anti-inflammatories
Ventricular septal defect or free wall rupture — rare mechanical complications that require emergency surgery
Recurrent MI — risk is significantly reduced by medications and rehabilitation, but recurrence is possible

FAQ

What should I do if I think I’m having a heart attack? Call emergency services immediately — 999 (UK), 911 (US), 112 (Europe). Do not drive yourself. Sit down comfortably. If you have aspirin and are not allergic to it, chew one 300 mg tablet. Unlock your door if alone. Do not wait to see if symptoms improve.

How is a heart attack diagnosed? With an ECG (which shows the electrical pattern of the heart) and troponin blood tests (which detect damage to heart muscle). A STEMI is identified immediately on the ECG; NSTEMI is confirmed over 1–3 hours through serial troponin measurements.

What is a stent? A small metal mesh tube placed inside a blocked coronary artery to keep it open. Most stents are drug-eluting — they release medication to prevent the artery from re-narrowing. Stent placement (PCI) is performed via a catheter through the wrist or groin, without open-chest surgery.

What is the difference between angioplasty and bypass surgery? Angioplasty (PCI) opens a blocked artery from the inside using a catheter and keeps it open with a stent — minimally invasive. CABG (bypass surgery) creates a new blood vessel pathway around the blockage using a vessel from elsewhere in the body — open-heart surgery. PCI is used for most straightforward blockages; CABG is used for complex multi-vessel disease or unsuitable anatomy.

What medications will I take after a heart attack? The standard post-MI bundle includes aspirin, a second antiplatelet drug (typically for 6–12 months after a stent), a high-intensity statin, an ACE inhibitor, and a beta-blocker. These are critical to long-term prevention — do not stop them without consulting your cardiologist.

When can I return to normal activities? Light activities within 1–2 weeks; most normal activities within 4–6 weeks for an uncomplicated MI. Cardiac rehabilitation provides a structured, supervised path back to full activity. Your team will advise on driving, work, and exercise based on your specific procedure and recovery.

What is cardiac rehabilitation and why is it important? Cardiac rehabilitation is a 6–12 week supervised programme of exercise, education, and psychological support after a cardiac event. It reduces mortality by approximately 20–25% compared with usual care alone. Every MI patient should be referred — ask if you haven’t been.