Heart
Acute Coronary Syndrome
A medical emergency, including heart attacks, where blood supply to the heart muscle is suddenly blocked.
Acute Coronary Syndrome (ACS) covers STEMI, NSTEMI, and unstable angina — all caused by sudden loss of blood flow to the heart and requiring urgent specialist care. Time-critical intervention is essential to prevent permanent cardiac damage or death.
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Acute coronary syndrome requires immediate medical attention, as a sudden blockage can quickly cause irreversible damage to the heart.
What Acute Coronary Syndrome Actually Means
Acute coronary syndrome (ACS) is the umbrella term for what happens when a coronary artery suddenly loses most or all of its blood flow. It covers two kinds of heart attack — STEMI and NSTEMI — and unstable angina, its close warning shot. In almost every case the trigger is the same: a cholesterol plaque in the artery wall cracks open, and a blood clot forms on top of it within minutes.
This is a time emergency. Heart muscle starved of blood begins to die within twenty to thirty minutes, and the amount saved depends almost entirely on how quickly the artery is reopened. In Singapore, where ischaemic heart disease is the second leading cause of death, the single most useful thing you can know is what the symptoms are and that the response is an ambulance, not a wait-and-see.
This is a time emergency. Heart muscle starved of blood begins to die within twenty to thirty minutes, and the amount saved depends almost entirely on how quickly the artery is reopened. In Singapore, where ischaemic heart disease is the second leading cause of death, the single most useful thing you can know is what the symptoms are and that the response is an ambulance, not a wait-and-see.
STEMI, NSTEMI, Unstable Angina: One Spectrum
The three labels describe how completely the artery is blocked and how much muscle is being lost. They matter because they set the clock.
- STEMI — a fully blocked artery, a distinctive ECG pattern, and rising cardiac enzymes. The artery must be reopened as fast as possible, ideally within 90 minutes of arriving at hospital.
- NSTEMI — a severely narrowed or intermittently blocked artery with a smaller amount of muscle damage on blood tests. Urgent, but the catheter procedure is usually done within 24 to 72 hours.
- Unstable angina — chest pain at rest or on minimal effort, with no muscle damage yet on blood tests. It signals a plaque on the verge of causing a heart attack and is treated as an emergency admission.
The Symptoms That Should Put You in an Ambulance
The textbook picture is a heavy, crushing pressure in the centre of the chest lasting more than a few minutes, often spreading to the left arm, jaw or back, with breathlessness, a cold sweat and nausea.
But a large minority — particularly women, people with diabetes and those over 75 — have none of that. They feel only unusual breathlessness, exhaustion, an indigestion-like ache, or discomfort in the upper back. If something feels badly wrong in the chest and it will not settle, do not talk yourself out of it. In Singapore, call 995. Do not drive yourself and do not book a ride — an ambulance crew can start treatment and defibrillate on the way.
But a large minority — particularly women, people with diabetes and those over 75 — have none of that. They feel only unusual breathlessness, exhaustion, an indigestion-like ache, or discomfort in the upper back. If something feels badly wrong in the chest and it will not settle, do not talk yourself out of it. In Singapore, call 995. Do not drive yourself and do not book a ride — an ambulance crew can start treatment and defibrillate on the way.
- Chest pressure or tightness lasting more than 10 minutes, or coming and going in waves
- Pain spreading to the arm, jaw, neck, upper back or both shoulders
- Breathlessness, cold sweat, nausea, light-headedness or a sense of dread
- In women and older adults: profound fatigue or ‘gastric’ discomfort with no clear cause
What Happens at a Singapore Emergency Department
You should have a 12-lead ECG within about 10 minutes of arrival — this is what separates a STEMI, which goes straight to the cath lab, from the rest. Blood is taken for troponin, a protein released by injured heart muscle, and repeated a few hours later to track the trend.
The major restructured hospitals — National University Hospital, the National Heart Centre at SGH, Tan Tock Seng, Changi — run 24-hour primary angioplasty services. If you are having a STEMI, a cardiologist threads a catheter from your wrist to the blocked artery, clears the clot and props the vessel open with a stent, often within an hour of your arrival.
The major restructured hospitals — National University Hospital, the National Heart Centre at SGH, Tan Tock Seng, Changi — run 24-hour primary angioplasty services. If you are having a STEMI, a cardiologist threads a catheter from your wrist to the blocked artery, clears the clot and props the vessel open with a stent, often within an hour of your arrival.
Treatment: Reopening the Artery, Protecting the Rest
For a STEMI, primary percutaneous coronary intervention (PCI) — balloon and stent — is the first choice. If you are far from a cath lab, a clot-dissolving drug is given first and PCI follows. For NSTEMI and unstable angina, you are stabilised with blood thinners and taken for angiography over the next day or two, with a stent or, for complex disease, bypass surgery.
Then the long game begins, and it is where most of the survival benefit lives:
Then the long game begins, and it is where most of the survival benefit lives:
- Dual antiplatelet therapy (aspirin plus a second agent) for 12 months, then usually aspirin for life
- A high-intensity statin aiming for LDL cholesterol below 1.4 mmol/L
- A beta-blocker and an ACE inhibitor to protect the heart's pumping function
- Cardiac rehabilitation — a supervised exercise and education programme that measurably lowers the risk of another event
Life After a Heart Attack
Most people who reach hospital in time recover well and return to work, driving and exercise within weeks. A structured cardiac rehabilitation programme — available at every restructured hospital in Singapore and worth asking for — roughly halves the chance of readmission and helps rebuild confidence.
Expect to stay on several medications indefinitely; stopping the antiplatelet or statin early is one of the commonest reasons for a second event. In Singapore you must not drive for at least four weeks after a heart attack, and longer for a vocational licence. It is normal to feel low or anxious for a while — tell your cardiologist, because it is treatable and it affects recovery. We follow patients closely from Paragon Medical Centre on Orchard Road through the first year, when the risk of a repeat event is highest.
Expect to stay on several medications indefinitely; stopping the antiplatelet or statin early is one of the commonest reasons for a second event. In Singapore you must not drive for at least four weeks after a heart attack, and longer for a vocational licence. It is normal to feel low or anxious for a while — tell your cardiologist, because it is treatable and it affects recovery. We follow patients closely from Paragon Medical Centre on Orchard Road through the first year, when the risk of a repeat event is highest.
Acute Coronary Syndrome: Common Questions
Concerned About Acute Coronary Syndrome?
Dr. Peter Chang offers specialist assessment and personalised management at Paragon Medical Centre, Singapore.