Heart Attack vs. Cardiac Arrest: Key Differences Every Patient Should Know

What is the difference between a heart attack and cardiac arrest?

A heart attack is a circulation problem — a blocked artery stops blood reaching part of the heart muscle. Cardiac arrest is an electrical problem — the heart suddenly stops beating altogether. Both are medical emergencies, but they have different causes, warning signs, and treatments. Deccan Hardikar Hospital in Pune provides emergency cardiac care for both conditions through its Cardiology and Emergency & ICU departments.

What are the warning signs of a heart attack vs. cardiac arrest?

Heart attacks typically announce themselves with warning signs that can appear minutes to hours — or even days — before the event. Cardiac arrest, by contrast, is almost always sudden and without prior warning.

Seven warning signs before a heart attack:

• Chest pain, pressure, tightness, or squeezing — often radiating to the left arm, jaw, neck, or back
• Shortness of breath, even at rest
• Cold sweats or clammy skin
• Nausea or vomiting
• Unexplained fatigue or weakness, especially in women
• Dizziness or light-headedness
• Discomfort in the upper abdomen, sometimes mistaken for indigestion

Five signs of cardiac arrest:

• Sudden collapse with no warning
• No pulse detectable
• No normal breathing (may show agonal gasping)
• Loss of consciousness within seconds
• Unresponsive to touch or voice

What causes a heart attack and what causes sudden cardiac arrest?

The underlying causes of these two emergencies are distinct, though they can overlap.

Common causes of a heart attack:

• Coronary artery disease (plaque build-up narrowing the arteries)
• Blood clot blocking a coronary artery
• Coronary artery spasm
• Risk factors: high blood pressure, high cholesterol, diabetes, smoking, obesity, and a sedentary lifestyle

Common causes of sudden cardiac arrest:

• Ventricular fibrillation — chaotic electrical signals causing the heart to quiver rather than pump
• Ventricular tachycardia — dangerously fast heart rhythm
• Structural heart disease (cardiomyopathy, heart failure)
• Severe electrolyte imbalances (potassium, magnesium)
• Drug toxicity or overdose
• Congenital heart conditions

The four types of cardiac arrest classified by underlying rhythm are: ventricular fibrillation (VF), pulseless ventricular tachycardia (pVT), pulseless electrical activity (PEA), and asystole (flatline). VF and pVT are shockable rhythms; PEA and asystole are not.

Which is more serious — cardiac arrest or a heart attack?

Cardiac arrest is immediately life-threatening in a way that a heart attack may not be. Without CPR and defibrillation within minutes, cardiac arrest is fatal. A heart attack is also a serious emergency, but the person is usually conscious and has a window of time to receive treatment.

• Cardiac arrest: survival depends on bystander CPR and defibrillation within 3–5 minutes of collapse.
• Heart attack: the faster a blocked artery is reopened (via angioplasty or clot-dissolving medication), the less heart muscle is permanently damaged.
• A heart attack that goes untreated can deteriorate into cardiac arrest.
• Cardiac arrest can occur without any prior heart attack.

Both conditions require immediate emergency response. Do not wait to see if symptoms improve on their own.

When should you go to hospital for chest pain or heart symptoms?

Seek emergency care immediately — do not drive yourself — if you experience any of the following:

• Chest pain or pressure lasting more than 5 minutes, or that goes away and returns
• Chest discomfort accompanied by shortness of breath, sweating, or nausea
• Pain radiating to the arm, jaw, neck, or back
• Sudden loss of consciousness in someone nearby — call emergency services and begin CPR at once
• Palpitations with dizziness or fainting
• Unexplained breathlessness at rest that does not resolve within a few minutes

If you witness someone collapse and become unresponsive with no normal breathing, call emergency services immediately, begin chest compressions, and use an AED if one is available. Every minute without CPR reduces survival chances significantly.

For non-emergency cardiac concerns — such as recurring chest tightness on exertion, unexplained fatigue, or a family history of heart disease — schedule a consultation with a cardiologist rather than waiting for a crisis. Early evaluation through our cardiology programme at Deccan Hardikar Hospital can identify risk factors before they become emergencies.

How does Deccan Hardikar Hospital in Pune support cardiac emergency patients?

Deccan Hardikar Hospital in Pune, located at Shivajinagar, is a NABH Pre-Accredited superspeciality hospital with five decades of surgical excellence. The hospital's Cardiac Sciences department works in close coordination with the Emergency & ICU team to provide rapid assessment and management for both heart attack and cardiac arrest presentations.

• Dedicated Emergency & ICU with round-the-clock cardiac monitoring
• Cardiology specialists supported by a multidisciplinary team
• In-house Histopathology Lab for rapid diagnostic support
• Transparent cost structure with patient-centric care
• Referral centre for trauma and cardiac cases across Western Maharashtra

For patients who require intervention beyond cardiac care — such as those with vascular complications — the hospital's trauma care and vascular surgery teams are available within the same facility. Patients requiring surgical evaluation can also access general surgery services without transfer to another centre.