When a celebrity or someone in the neighbourhood collapses, the news says "heart attack" or "cardiac arrest" as if the two words mean the same thing. Most of us have used them that way too. But they're different emergencies, with different causes, different first aid and different tests.
Knowing which is which can genuinely help you act faster when seconds count.
Cardiac Arrest vs Heart Attack: The Simple Difference
The easiest way to remember it: a heart attack is a plumbing problem, and cardiac arrest is an electrical problem.
- Heart attack (myocardial infarction): The heart’s blood vessel becomes blocked, generally by a clot that forms on top of the fatty deposits. The part of the heart becomes deprived of blood and damage to the tissue occurs. The heart continues to function; the patient remains conscious.
- Sudden cardiac arrest: The heart's electrical activity is affected; it results in an irregular heart rhythm. No proper pumping of blood occurs, depriving the brain and body of blood supply. The individual is unable to maintain consciousness and normal breathing.
To conclude, the heart attack is a problem in blood circulation whereas cardiac arrest is a problem in the heart’s rhythm. And this is how the relationship between the two works: a heart attack can result in cardiac arrest, though not all heart attacks cause the latter.
Heart Attack Symptoms You Shouldn't Ignore
Heart attack symptoms often build up over minutes or even hours. They include:
- Pressure, tightness or heaviness in the chest (not always sharp pain)
- Pain or discomfort spreading to the left arm, shoulder, jaw, neck or back
- Breathlessness
- Cold sweat, nausea or vomiting
- Unusual tiredness, dizziness or lightheadedness
Older people, women, and those with diabetes may show milder symptoms, such as feeling tired, heartburn symptoms, or back or jaw pain without having much chest pain. Hence, it can be a risky assumption to say that “It’s just acidity.”
Sudden Cardiac Arrest Symptoms: Often Little Warning
Sudden cardiac arrest is exactly that: sudden. The person suddenly:
- Collapses and falls to the ground
- Doesn't respond when you shout or tap their shoulders
- Isn't breathing, or is only gasping
- Has no pulse
Some people notice warning signs in the days or weeks before, like palpitations, fainting spells, dizziness or unexplained chest discomfort. These should never be brushed off, especially in someone with a family history of sudden death.
What to Do: Cardiac Arrest vs Heart Attack First Aid
If you suspect a heart attack:
- Call emergency services (112, or an ambulance service such as 108) immediately.
- Keep the person calm, seated and resting. Loosen tight clothing.
- Don't let them drive themselves to the hospital.
- Give medicines like aspirin only if a doctor has advised it or the emergency team tells you to.
If you suspect cardiac arrest:
- Call an ambulance right away, or ask someone nearby to do it.
- Start CPR immediately. Push hard and fast in the centre of the chest, at about 100 to 120 compressions a minute, without stopping.
- If an AED (automated external defibrillator) is nearby, use it. It gives clear voice instructions.
- Keep going until help arrives.
Bystander CPR can double or triple survival chances, so it's worth attending a basic CPR training session. You don't need to be a doctor to save a life.
Which Tests Detect a Heart Attack?
When someone arrives at hospital with chest pain, doctors usually move fast with a few key tests:
- ECG (electrocardiogram): measures the electrical activity of the heart; signs of heart attack can be identified in minutes.
- Troponin test: very important test, since it indicates the level of troponin – protein that appears in the blood in case of injury to the heart muscle. Very sensitive test, can indicate even the smallest amount. Sometimes done after a few hours, since the amount of protein increases over time.
- Echocardiogram: ultrasound test, shows the state of the work of heart and its weaker spots.
- Coronary angiography: X-ray dye test that helps identify which artery is blocked.
Troponin test normal levels: These vary depending on the laboratory and the specific assay performed (troponin I or troponin T, regular sensitivity or high sensitivity). Please do not compare your results to the normal ranges found elsewhere but check them against the ranges listed on your own report. Increased troponin suggests heart muscle damage, but it must be interpreted in light of other symptoms and your ECG findings.
Which Tests Detect Sudden Cardiac Arrest?
Cardiac arrest is recognised on the spot: no pulse, no breathing, no response. There's no test needed to confirm it in the moment. Tests come afterwards, to find out why it happened, and to prevent a repeat:
- ECG and heart rhythm monitoring (such as a Holter monitor) to look for dangerous rhythm problems
- Blood tests including troponin, and electrolytes like potassium and magnesium, since imbalances can upset the heart's rhythm
- Echocardiogram to check for weak heart muscle, thickened walls or valve problems
Coronary angiography to look for blocked arteries - Electrophysiology (EP) study or genetic testing in selected cases, such as young patients or those with a family history of sudden death
In some survivors, a small device called an ICD (implantable cardioverter-defibrillator) is fitted to correct dangerous rhythms in the future.
Checking Your Risk Before Cardiac Arrest vs Heart Attack Strikes
The best test is always the one taken before a crisis arises. Both diseases have common risk factors: hypertension, diabetes, high cholesterol, smoking, obesity, stress, lack of physical activity, and family history of heart disease. Indians have a tendency to get heart diseases at a younger age compared to other people.
Therefore, getting tested at 50 years old might be quite late. Some tests that are usually included in a simple prevention heart screening test include lipid test, blood sugar, HbA1c, blood pressure, and ECG. In some cases, a treadmill test and echo may also be suggested by your doctor.
Conclusion
In the cardiac arrest vs heart attack comparison, the lesson is simple: both are emergencies, but they need different responses. Chest pressure and sweating? Call for help and rest. Someone collapsed and was not breathing? Call for help and start CPR. And don't wait for an emergency to learn your numbers.
You can book a lipid profile, HbA1c, cardiac markers or a full heart health checkup with Dr. B. Lal Clinical Laboratory, a NABL-accredited diagnostic lab, with home sample collection available in many cities.
