Heart attack vs cardiac arrest: what’s the difference?

What is a heart attack?

A heart attack occurs whenblood flow to a part of the heart muscle is blocked, usually because of a clot in a coronary artery.

• The heart muscle begins to suffer damage due to lack of oxygen

• Symptoms often include chest pain or pressure, sweating, nausea, breathlessness, pain radiating to the arm, jaw or back

• The heart usually continues to beat, though it is injured

In simple terms, a heart attack is acirculation problem— the plumbing is blocked.

What is cardiac arrest?

Sudden cardiac arrest (SCA) is anelectrical failure of the heart.

• The heart abruptly stops beating or beats chaotically

• Blood flow to the brain and vital organs ceases immediately

• The person collapses, loses consciousness and hasno pulse

• Death can occur within minutes without intervention

Cardiac arrest often strikeswithout warningand requiresimmediate CPR and defibrillationto restore a survivable rhythm.

In short, cardiac arrest is anelectrical problem— the heart stops.

How the two are connected (and why people confuse them)

A heart attackcan triggercardiac arrest if the damaged heart muscle disrupts the heart’s electrical system. However:

• Not all cardiac arrests are caused by heart attacks

• Many result from arrhythmias, heart failure or structural heart conditions

This overlap explains the confusion, but medically, the two emergencies are very different — and demand different responses.

Why this distinction matters

• Heart attack:Call emergency services immediately; treatment focuses on restoring blood flow

• Cardiac arrest:Begin CPR immediately and use an AED if available —seconds matter

Public awareness of CPR and access to automated defibrillators dramatically improves survival chances in cardiac arrest cases.

The takeaway

A heart attack blocks blood flow.Cardiac arrest stops the heart altogether.

Understanding this difference — and knowing how to respond — can mean the difference between life and death.