A heart attack is a piece of heart muscle dying because the artery that feeds it has been blocked by a clot. That is the common kind, and it is what most of this topic is about. But the same word covers a heart stunned by stress, an artery torn rather than blocked, a heart attack with clean arteries, and a heart stopped by its own electrics, and the treatments and the futures differ. This topic is the map of all of them, what the hospital should do for each and how fast, and what should happen in the years after. Prevention — cholesterol, blood pressure, the calculator — is the heart topic; the cardiac arrest itself is the resuscitation chapter.
1. Recognising it
Two-thirds of heart attacks are the classic picture: a band of pressure across the chest, spreading to the arm or jaw, with sweating and dread. The other third are breathlessness alone, "indigestion", jaw or arm pain, a collapse, a racing heart, or a sudden overwhelming tiredness — more often in women, in people with diabetes and in the old. The recognising chapter goes through each, what to do in the first minutes, and the three things that make people wait.
2. Which kind
The hospital sorts chest pain with three tests. The ECG says whether an artery is completely blocked (a STEMI) or not. The troponin blood test, repeated on a timed pathway, says whether muscle has died. The angiogram shows the artery and treats it. From those three come the diagnoses: STEMI, NSTEMI, unstable angina, the type 2 heart attack caused by another illness, the heart attack with clean arteries, the torn artery, the stress heart, and the inflamed heart that mimics all of them. The spectrum chapter is the map, with a table that tells them apart.
3. What should happen in hospital
An ECG within ten minutes
In the ambulance or at the door.
A STEMI: the artery opened within 120 minutes
A stent through the wrist, in a heart attack centre, bypassing the local hospital if need be. A clot-busting drug if the centre cannot be reached in time.
Everyone else: a troponin answer within one to three hours
And if it is a heart attack, an angiogram within 72 hours, sooner if unstable.
The drugs, each with a reason
Aspirin and a second antiplatelet, an anticoagulant until the artery is treated, a high-intensity statin, an ACE inhibitor, a beta-blocker where the pump is weakened, oxygen only if it is needed.
An echocardiogram before discharge
How much of the pump was lost decides half the drugs and, later, whether a defibrillator is needed.
Cardiac rehabilitation, referred before you leave
It reduces deaths and readmissions by around a quarter and half of eligible people never attend.
The clock chapter has each step by NICE recommendation with the numbers behind it, cardiogenic shock, and the point where the 2025 evidence on beta-blockers has moved ahead of the UK guideline.
4. The rhythm problems and heart block
A heart can be in trouble without a blocked artery. Atrial fibrillation, the commonest sustained rhythm disorder, is not immediately dangerous but causes a fifth of strokes. Supraventricular tachycardia is frightening and curable. Ventricular tachycardia and fibrillation are the rhythms of collapse and arrest. Heart block, where the signal from the top of the heart to the bottom is delayed or cut, ranges from harmless to a pacemaker. The rhythm chapter takes each in turn with the decisions and the numbers; the arrest is in the resuscitation chapter. The five conditions that arrive as a heart attack and part company with it — the stunned heart, the torn artery, the clean-artery heart attack, the inflamed muscle and the inflamed sac — are the unusual-ones chapter.
5. The years after
Four jobs: the drugs, reviewed rather than repeated; the tests that find why it happened and whether it will happen again, including the genetic ones for early or unexplained heart attacks; cardiac rehabilitation; and the changes to daily life, driving and work that move the risk. The after-hospital chapter has the drugs with their durations, the rehab, the DVLA and flying rules, and the review schedule; the every-test chapter lists every blood, genetic and imaging test in tiers with what each result changes; and the printable checklist puts it on one sheet.
6. Where UK and US guidance differ
The American cardiology societies published a full new heart-attack guideline in February 2025; the UK works to NICE's 2020 guideline and NICE's 2023 lipid guidance. They agree on the clock, the wrist, the drugs and the rehab. The US is ahead on three things: ezetimibe from the first day and a lower cholesterol trigger; shortening the second antiplatelet where bleeding risk is high; and a mechanical pump for cardiogenic shock that saved lives in a 2024 trial. On beta-blockers after a heart attack that left the pump intact, both are being overtaken by the 2025 trials, and NICE's twelve-months-for-all is the position furthest behind. Each chapter ends with the differences that apply to it.