Sudden cardiac arrest

Sudden cardiac arrest (SCA), also known as sudden cardiac death, is when the heart suddenly and unexpectedly stops beating as a result of an arrhythmia. When this occurs, blood stops flowing to the brain and other vital organs. SCA usually causes death if not treated in minutes.


SCA is not the same thing as a heart attack. A heart attack is a problem with blocked blood flow to a part of the heart muscle. In a heart attack, the heart usually does not suddenly stop beating. SCA, however, may happen during recovery from a heart attack.


People with heart disease have a higher chance of having SCA. But most SCAs happen in people who appear healthy and have no known heart disease or other risk factors for SCA.


As per WHO census statistics mortality due to cardiac causes has overtaken mortality due to all cancers put together. Approximately 4280 out of every one lakh people die every year from SCA in India alone



Abnormalities in the Heart’s electrical System can cause SCA.

V-fib is a cardiac condition in which the ventricles (the heart’s lower chambers) don’t beat normally. Instead, they quiver very rapidly and irregularly. When this happens, the heart pumps little or no blood to the body. V-fib is fatal if not treated within a few minutes. Other problems with the heart’s electrical system also can cause SCA. For example, SCA can occur if the rate of the heart’s electrical signals becomes very slow and stops. SCA also can occur if the heart muscle doesn’t respond to the heart’s electrical signals.

Coronary Heart Disease

CHD is a disease in which a waxy substance called plaque (plak) builds up in the coronary arteries. These arteries supply oxygen-rich blood to your heart muscle. Plaque narrows the arteries and reduces blood flow to your heart muscle. Eventually, an area of plaque can rupture (break open). This may cause a blood clot to form on the plaque’s surface, narrowing the Arteries leading to Heart Attacks.

During a heart attack, some heart muscle cells die and are replaced with scar tissue. The scar tissue damages the heart’s electrical system. As a result, electrical signals may spread abnormally throughout the heart. These changes to the heart increase the risk of dangerous arrhythmias and SCA.

Intense Physical Exercise:

Intense physical activity. The hormone adrenaline is released during intense physical activity. This hormone can trigger SCA in people who have heart problems. Very low blood levels of potassium or magnesium. These minerals play an important role in your heart’s electrical signaling. Major blood loss. Severe lack of oxygen.

Inherited Disorders:

A tendency to have arrhythmias runs in some families. An example of an inherited disorder that makes you more likely to have arrhythmia is LQTS- Long QT Syndrome. LQTS is a disorder of the heart’s electrical activity. Problems with tiny pores on the surface of heart muscle cells cause the disorder. LQTS can cause sudden, uncontrollable, dangerous heart rhythms.

Structural Changes in the Heart:

Changes in the heart’s normal size or structure may affect its electrical system. Examples of such changes include an enlarged heart because of High Blood Pressure or advanced heart disease. Heart infections also may cause structural changes in the heart


Signs & Symptoms


Usually, the first sign of sudden cardiac arrest is loss of consciousness, which is similar to fainting. At the same time, breathing often stops and no heartbeat (or pulse) can be felt. Some people may first notice that they have a racing heartbeat or feel dizzy or lightheaded just before they faint.


Treatment and Prevention:


SCA requires immediate treatment with a device called a defibrillator, which delivers an electrical shock to the heart. Successful defibrillation restores normal rhythm to the heart. Defibrillation must be provided within minutes after SCA to avoid permanent damage to the body and brain and to prevent death. With every minute of delay in providing defibrillation, the chances of surviving SCA drop rapidly. People experiencing SCA should be given cardiopulmonary resuscitation (CPR) until they can be treated with a defibrillator.


Special defibrillators called automated external defibrillators (AEDs) can be used by untrained bystanders in an emergency. AEDs are becoming increasingly available at public places, such as airports, office building, and shopping centers. People who survive SCA may need an implantable cardioverter defibrillator to help prevent death if another SCA happens. Beta-blocker drugs also help reduce the chance of death from SCA in people with known heart disease.


Heart-healthy lifestyle choices as below may lower people’s chances for SCA.

  • Heart Healthy Eating
  • Aiming for a Healthy Weight
  • Managing Stress
  • Being Physically Active
  • Quit Smoking

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