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Cardiac Arrest

What is cardiac arrest?

Cardiac arrest is defined as the sudden loss of blood flow normally due to heart failure of the contract effectively. Cardiac arrests usually result from an electrical disturbance in your heart that disrupts the pumping action and stops the flow to your body. 

Sudden cardiac arrest or SCR can be are the result of blocked blood flow in the part of your heart. Sudden cardiac arrest is different from a heart attack. 

A sudden cardiac arrest can lead to death if not treated immediately. Giving cardiopulmonary resuscitation (CPR), by giving chest compressions appropriately or by using a defibrillator can improve the chances of survival until the emergency team arrives. 

Classification of cardiac arrest based on ECG rhythm:

  • Shockable: Ventricular fibrillation and pulseless ventricular tachycardia.
  • Non-Shockable: Asystole and pulseless electrical activity.  

Causes of cardiac arrest

An arrhythmia- problem in your heart that results in problems with your heart ‘s electrical system, is the usual cause of having a sudden cardiac arrest. 

The heart’s electrical system is responsible for controlling the rate and rhythms of the heartbeat. If anything seems wrong, your heart may beat too fast, too slow or irregular beating is noted (arrhythmia). Arrhythmia can often brief and harmless, but in some cases, it may lead to sudden cardiac arrest.    

Types of causes of cardiac arrest

There are two types of cardiac arrest causes, these include: 

Extracardiac causes

  • Extracardiac causes are related to all cases that are accompanied by hypoxia (low oxygen in the blood). These causes include:
  • Non-trauma related bleeding such as gastrointestinal bleeding, intracranial hemorrhage, and Aortic rupture.
  • Overdose of medications
  • Trauma
  • Drowning
  • Pulmonary embolism


Cardiac causes

Heart attack: A heart attack can result in severe coronary artery disease. It may trigger ventricular fibrillation and sudden cardiac arrest. 

Cardiomyopathy (Enlargement of the heart): When heart’s muscle walls stretch, enlarged and thickened heart condition occurs. Your heart muscles are abnormal. 

Valvular heart disease: Narrowing and leaking of heart valves may lead to stretching or thickening of the muscles of the heart. 

Congenital heart disease: Sudden cardiac occurs in children or in adults. It can be a result of a heart defect detected at the time of birth. 

Electric problems in heart: In some persons, the problem is in the electrical system of the heart instead of a problem related to heart muscles or valves. 

Hypersensitive heart disease: This refers to the heart conditions that are caused by high blood pressure. These include heart failure, thickening or narrowing of heart valves, coronary artery disease, and other heart-related conditions. 

Risk factors of cardiac arrest

Sudden cardiac arrests are often related to coronary artery disease, there are some factors that put you at risk of sudden cardiac arrest and can also put you at risk of coronary artery disease. These risk factors include:

  • Family history of coronary artery disease
  • High blood pressure
  • High blood cholesterol
  • Obesity
  • Diabetes
  • A sedentary lifestyles


Other risk factors that might increase your risk of sudden cardiac arrest include:

  • A previous heart attack
  • Already have an episode of cardiac arrest or a family history of cardiac arrest
  • A personal family history of other heart diseases such as heart rhythm, disorders, congenital heart defects, heart failure, cardiomyopathy, etc
  • Age- the risk of having a cardiac arrest increases with age
  • Sex- men have three-time greater risk of having cardiac arrest than women
  • Consumption of illegal drugs like cocaine or amphetamines
  • Nutritional imbalance: low potassium or magnesium levels in your blood
  • Obstructive sleep apnoea
  • Chronic kidney disease

Symptoms of cardiac arrest

The signs and symptoms of sudden cardiac arrest are immediate and drastic; these include:

  • Sudden collapse
  • No pulse
  • No breathing
  • No blood pressure
  • Loss of consciousness
  • Seizure may or may not occur
  • Death like appearance
  • Cyanosis (lips and nails start appearing blue)


You may experience other signs and symptoms that occur before the cardiac arrest. These might include:

  • Chest discomfort
  • Shortness of breath
  • Weakness
  • Palpitations

However, the sudden cardiac arrest often occurs with no warning.


A sudden cardiac arrest results in reduced blood flow to the brain that causes unconsciousness. If the heart rhythm does not return rapidly to normal, it may lead to brain damage that can cause death. 

Diagnosis of cardiac arrest

If you survive sudden cardiac arrest, your health care provider will perform some diagnostics tests to know what was the cause and to prevent future episodes. these tests include:

Electrocardiogram (ECG): ECG is done to detect the electrical activity of your heart. Getting an ECG can reveal a disturbance in heart rhythm or it may detect abnormal electrical patterns, like a prolonged QT interval, that increases your risk of sudden death.

Blood tests: Blood tests can be done to check the levels of potassium, magnesium, hormones, and other chemicals related to the heart’s function. Some other blood tests may also perform that can detect recent heart injury and heart attacks. 

Imaging tests: 

Chest Xray:  Having a chest x-ray can help your doctor or health care provider to check the shape and size of your heart.

Echocardiogram: This test image of your heart is produced by using sound waves. This can help to identify the damaged area in your heart.

Nuclear scan: This test helps to identify blood flow problems in your heart. This test is usually done with a stress test. A small amount of radioactive material injected into your bloodstream. Learn more about this. 

Coronary catheterization (angiography): In this process, a liquid dye is injected into the arteries of your heart with the help of a catheter (long thin tube). As the dye reaches the arteries and fills it, the arteries become visible on x-ray or fluoroscopy. This will help your doctor or health care provider to see the area of blockage.

Management & Treatment of cardiac arrest

  1. Basic life support (BLS)
  2. Advance cardiac life support (ACLS)
  3. Pediatric advance life support (PALS)
  4. Neonatal resuscitation program (NRP)


Treatment of cardiac arrest

A sudden cardiac arrest needs immediate action for survival.

  • CPR (Cardio Pulmonary Resuscitation)

For treating sudden cardiac arrest immediate CPR is crucial. It works by maintaining a flow of oxygen-rich blood to the body’s vital organs. CPR may provide a vital link until a more advanced emergency care team is available. 

  • Defibrillation
  • Therapeutic hypothermia
  • Extracorporeal membrane oxygenation devices
  • Long term treatments include
  • Medications such as anti-arrhythmic drugs
  • Implantable cardioverter-defibrillators (ICD)
  • Coronary angioplasty
  • Coronary bypass surgery
  • Radiofrequency catheter ablation
  • Correlative heart surgery

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