What is Cardiac Arrest?

Cardiac arrest occurs when the heart fails to pump blood properly, resulting in a sudden decrease in blood flow in the body. Consequently, the body is deprived of oxygen leading to a life-threatening condition requiring immediate cardiopulmonary resuscitation (CPR) until further treatment. A Cardiac arrest causes fast loss of consciousness and irregular or complete stoppage of respiration.

Causes of Cardiac Arrest

The most prevalent cardiac arrest causes is an abnormal heart rhythm (arrhythmia) when your heart's electrical circuitry malfunctions.

The electrical system controls the heart's rate and rhythm.  As a result, it may beat too rapidly, too slowly, or irregularly (arrhythmia). While most arrhythmias are transient and harmless, some can lead to cardiac arrest.

At the time of cardiac arrest, the most common heart rhythm is an arrhythmia in the lower chamber (ventricle). Due to fast, erratic electrical impulses, your ventricles quiver ineffectively instead of pumping blood (ventricle fibrillation).

Sudden cardiac arrests may happen even to those with no known heart issues. On the other hand, a life-threatening arrhythmia is more common in people who have a previously undiagnosed heart condition. Here are some of the causes:

  • Coronary artery disease: It is a type of cardiovascular illness in which the arteries become clogged with cholesterol and other deposits. People with coronary artery disease are more likely to experience sudden cardiac arrest.
  • Heart failure: A heart attack, most commonly caused by severe coronary artery disease, can cause ventricular fibrillation and abrupt cardiac arrest. A heart attack at times causes to form scar tissue in your heart. Electrical short circuits around scar tissue might cause heart rhythm irregularities.
  • Valvular heart disease: Leaking or narrowing of the heart valves might cause the heart muscle to expand or thicken. 
  • Arrhythmia is more prone to develop when the chambers become bigger or weaker due to stress caused by a tight or leaking valve.
  • A birth defect in the heart (congenital heart disease): In children or adolescents, congenital heart disease often proves to be the cause of cardiac arrest. Adults who have undergone surgery to correct a congenital heart defect are vulnerable to sudden cardiac arrest.


When a sudden cardiac arrest happens, the brain's blood supply is cut off, resulting in unconsciousness. In case your heart rhythm does not return to normal, you will suffer brain damage and die. In cardiac arrest survivors, brain impairment may be evident.


Getting regular checkups, having your heart tested, and living a heart-healthy lifestyle reduces the risk of unexpected heart attacks. In addition, participating in physical and sporting activity significantly lowers the risk of sudden cardiac arrest.