Heart Conditions — Emergency
Heart Attacks
Explained
A heart attack is a life-threatening emergency where a coronary artery becomes suddenly blocked. Understanding the signs, the timeline, and the treatments can save your life — or the life of someone close to you.
Understanding the Condition
What is a Heart Attack?
Heart attacks represent a life-threatening emergency where a coronary artery suddenly becomes blocked by a blood clot. The underlying process typically begins with atherosclerosis — the accumulation of cholesterol and inflammatory material within the artery wall. When plaque ruptures, it exposes collagen, triggering rapid clot formation. Because coronary arteries are narrow, even small clots can completely obstruct blood flow.
When blood supply to heart tissue is interrupted, that region stops functioning immediately, producing characteristic symptoms. Rapid intervention to restore blood flow can halt the attack and limit damage.
Notably, patients with minimal plaque disease can experience more severe attacks than those with established coronary disease, because their hearts have not adapted to reduced blood supply. Patients with known coronary narrowing often experience stable angina — discomfort during exertion that resolves with rest — which can be effectively managed with medications that substantially reduce heart attack risk.
"Time is muscle — every minute of arterial blockage destroys more heart tissue. The fastest path to survival is dialling 999 and getting to a Heart Attack Centre."
Recognising a Heart Attack
Symptoms to Act On Immediately
Heart attacks can develop at any time, including during sleep, and are frequently triggered by stress-related blood pressure surges. Most patients describe a sensation of heavy weight on their chest rather than sharp pain.
- Heaviness or tightness across the chest — like a band being tightened around the ribcage
- Pain radiating into the arm, neck, back, or jaw (classically the left arm, but either or both sides)
- Anxiety, sweating, coldness, and clamminess
- Nausea or vomiting
- Brief episodes of brief relief followed by return of symptoms (suggesting temporary arterial reopening)
- Symptoms that intensify over time — a critical warning sign requiring immediate action
Call 999 (UK) immediately and report severe crushing chest pain and your location. If alone, move to your front door and open it before collapsing. Do not drive yourself to hospital.
Immediate Response
The First Steps of Treatment
Immediate hospital assessment is essential for all suspected heart attacks. Every minute of delay increases the damage to heart muscle, so the speed of response is critical.
- 1
ECG & Aspirin — Paramedics perform a 12-lead ECG and administer Aspirin 300mg (ideally chewed) on arrival.
- 2
GTN Spray — Glyceryl trinitrate spray or sublingual tablets dilate coronary arteries. In some cases GTN can halt or slow the attack.
- 3
Heart Attack Centre — In London, patients with specific ECG findings are taken directly to a dedicated Heart Attack Centre staffed 24/7/365.
- 4
Blood Thinners — On arrival, treatment includes high-dose antiplatelet therapy (aspirin with clopidogrel, ticagrelor, or prasugrel) plus heparin injection.
- 5
Coronary Angiography — Imaging of the coronary arteries to identify the blockage and guide angioplasty to reopen the artery.
Types of Heart Attack
STEMI & NSTEMI
Heart attacks are classified by their ECG appearance, which determines the urgency and type of treatment required.
STEMI
ST-Elevation Myocardial Infarction
STEMI occurs when a coronary artery is completely blocked. The ECG shows a characteristic ST-segment elevation. Heart muscle is being actively destroyed — every second counts.
The Left Anterior Descending (LAD) artery blockage can cause severe scarring and weakened heart function. The Right Coronary Artery (RCA) blockage may disrupt the heart's electrical conducting system, causing Complete Heart Block.
NSTEMI
Non-ST-Elevation Myocardial Infarction
NSTEMI occurs when the artery is partially blocked. Blood markers (troponin) confirm heart muscle damage, though the characteristic ST-elevation is absent on the ECG.
Treatment depends on risk scores and clinical progression. Blood thinners are started immediately. Coronary angiography typically follows within 24–72 hours, guided by the degree of risk.
If Left Untreated
Potential Complications
Untreated heart attacks beyond 12 hours typically result in extensive cardiac damage. Heart muscle that does not receive blood dies and is replaced by scar tissue — this cannot be reversed.
The COVID-19 pandemic demonstrated the consequences of delayed presentation: many patients arrived late with substantial arterial clots that proved significantly harder to treat and with far greater resulting damage.
Early hospital presentation, even if symptoms seem manageable, is always the correct course of action.
Heart Failure
Severe damage to the pumping muscle causes acute lung flooding with fluid, producing severe breathlessness. Long-term heart failure carries a prognosis worse than many cancers.
Arrhythmia
Extensive scarring disrupts electrical conduction. Ventricular tachycardia and ventricular fibrillation are life-threatening without immediate electrical cardioversion.
Valve Disruption
Scarring of valve-supporting structures causes acute mitral or tricuspid regurgitation with sudden pulmonary oedema. Emergency surgical repair carries very high risk.
Cardiac Thrombus
Portions of non-contracting heart wall allow clots to form inside the chamber. These clots can travel to the brain, causing devastating and potentially permanent stroke.
Holes in the Heart
Large areas of dead muscle can rupture, creating a hole in the heart wall. This is a surgical emergency requiring immediate intervention.
Cardiac Arrest
The most serious complication. Ventricular fibrillation causes the heart to stop pumping entirely. Without immediate CPR and defibrillation, death follows within minutes.
After the Event
Medicines Required
After a Heart Attack
Following a heart attack, a combination of medications is prescribed to prevent recurrence, protect remaining heart function, and stabilise the coronary arteries. These medications are typically life-long and should not be stopped without cardiology advice.
Aspirin
Antiplatelet — Blood Thinner
Prescribed to nearly all patients to reduce recurrent heart attack risk. Standard dose is 75mg daily, ideally taken with food. Aspirin can cause stomach ulcers in vulnerable patients and must not be discontinued without cardiologist guidance.
Dual Antiplatelet Therapy
Antiplatelet — Blood Thinner (Combined with Aspirin)
A second antiplatelet agent combined with aspirin significantly reduces recurrent heart attack risk and prevents stent thrombosis — a life-threatening re-blockage of a treated artery.
Clopidogrel (75mg daily) has been used since the late 1990s and is very safe. Ticagrelor (90mg twice daily) is more potent and may cause a harmless sensation of needing a deeper breath. Prasugrel (10mg daily) is the strongest option, reduced to 5mg in patients over 75 or weighing under 60kg.
Duration: at least 12 months following a heart attack or stent placement.
- Clopidogrel
- Ticagrelor
- Prasugrel
Statin
Cholesterol-Lowering — Lipid Modifier
Statins reduce blood cholesterol by modifying a liver enzyme responsible for cholesterol production. Derived originally from Chinese red yeast rice extracts, they have been studied for over 30 years.
Following a heart attack, statins are typically started on the day of the event. They also act to stabilise the ruptured plaque that triggered the attack. Common post-attack choices include atorvastatin (40–80mg) or rosuvastatin.
- Atorvastatin
- Rosuvastatin
- Pravastatin
Beta-Blocker
Heart Rate & Workload Reduction
Beta-blockers calm heart muscle and prevent excessive rate acceleration, reducing cardiac strain after a heart attack. Patients with scarring or reduced function remain on them long-term due to association with prolonged survival.
Side effects can include initial fatigue, cold hands and feet, and occasionally erectile dysfunction in men — all should be reported to Dr Nijjer.
- Bisoprolol
- Carvedilol
ACE Inhibitor
Heart Protection — Blood Pressure
Ramipril and perindopril are blood pressure medications with additional cardiac benefits. They block an abnormal kidney-triggered pathway that worsens heart function, making them a mainstay for all patients with any degree of heart muscle weakness.
Approximately 10% of patients develop a recurrent dry cough, in which case Dr Nijjer may switch to an ARB such as candesartan or irbesartan, which offer similar cardiac benefits without this side effect.
- Ramipril
- Perindopril
- Candesartan (ARB)
Additional Medications
Emerging Therapies — Research-Guided
Emerging evidence supports further medications that improve post-attack heart function. These include extra anticoagulants such as rivaroxaban, and SGLT2-inhibitors originally developed for diabetes (dapagliflozin, empagliflozin, canagliflozin), which have been shown to reduce hospitalisation for heart failure and cardiovascular death.
Dr Nijjer prescribes these based on the latest research evidence.
- Rivaroxaban
- Dapagliflozin
- Empagliflozin
Life After a Heart Attack
Recovery & Cardiac Rehabilitation
Cardiac rehabilitation programmes educate patients on the lifestyle modifications necessary to reduce the risk of further events. Many patients resume normal activity within weeks of a successful angioplasty — a testament to the effectiveness of modern emergency cardiac care.
Dr Nijjer tailors guidance on diet, exercise, and activities specifically to each patient's circumstances, taking into account the extent of any damage, the medications prescribed, and the patient's own goals and lifestyle.
Dr Nijjer's Expertise
Dr Nijjer is the Lead for Cardiac Catheter Laboratories at Hammersmith Hospital and a Principal Investigator in multiple major international studies. He has treated thousands of patients with acute coronary syndromes using the latest angioplasty techniques, including iFR-guided intervention, intravascular imaging, and complex calcium modification.
Related Conditions
Further Reading
Concerned about your heart health?
Dr Nijjer offers expert cardiology consultations at 68 Harley Street and across four London clinic sites. Whether you have had a heart attack or are concerned about your risk, arrange an appointment today.