Cardiac arrest/ Sudden cardiac arrest (CSA) is when the heart suddenly and unexpectedly stops beating; It  is the abrupt loss of heart function in a person.
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A cardiac arrest happens when the heart stops pumping blood around the body, which accompanies collapsing without warning. The heart stops beating, and blood stops flowing to the brain and other organs. within a few seconds, breathing stops and there is no pulse.
Cardiac arrest risk is higher for men after age 45 and for women after age 55.
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**Difference between a heart attack and a cardiac arrest**

**A heart attack** is when one of the coronary arteries supplying blood to the heart muscle becomes blocked. The affected part of the heart muscle will start to die because it is not getting oxygen. **A cardiac arrest**occurs when a person’s heart stops pumping blood round their body and they stop breathing.

When a person has a cardiac arrest, they become unresponsive and lose consciousness almost immediately. Signs of life stop – such as normal breathing – and the person turns grey very quickly.Cardiac arrest is the ultimate medical
emergency in the medical world.
When a person has a cardiac arrest, it is sometimes possible to shock the heart back into a normal heart rhythm by giving the heart an electrical shock using a **defibrillator**.

**Causes Of Cardiac Arrest**
Cardiac arrest can happen at any age, and may be caused by:

* Heart and circulatory disease (eg. a heart attack)
* Acute Myocarditis (inflammation of the heart muscle)
* extreme blood or fluid loss
* Congenital heart disease
* extreme body temperature (both too high or too low)
* Inherited disorders 
* blood potassium levels that are too high or too low
* a lack of oxygen
* a punctured lung
* blood clot/s in the lung or coronary arteries
* poisoning
* a collection of blood around the heart – usually after an injury such as a
stabbing

**Signs And Symptom Of Sudden Cardiac Arrest**

* Sudden collapse.
* Sudden unresponsiveness to touch or sound.
* Abnormal or no breathing.
* Chest pain
* Discomfort in one or both arms or in the back, neck, or jaw
*  Nausea (feeling sick to the stomach), or vomiting

** Diagnosis**
* EKG (Electrocardiogram)
EKG is a simple, painless test that detects and records the heart's electrical activity.

* Echocardiography
Echocardiography, or echo, is a test that uses sound waves to create pictures of your heart. The test shows the size and shape of your heart and how well your heart chambers and valves are working.

* Electrophysiology Study
Doctors use cardiac catheterization to record how the heart's electrical system responds to certain medicines and electrical stimulation. This helps to find where the heart's electrical system is damaged.

* Blood Tests
Doctors may recommend blood tests to check the levels of potassium, magnesium, oxygen level and other chemicals in your blood. These chemicalsare important in the heart's electrical signaling.

**Treatment**

It is possible to survive and recover from a cardiac arrest. Sudden cardiac arrest (SCA) is an emergency and should treated with a defibrillator immediately.
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If a patient survives SCA, he should be admitted at the hospital for ongoing care and treatment, where the medical team will closely watch the heart.
The cause of the arrest will be looked into. If patient is diagnosed with coronary heart disease,the patient have to undergo percutaneous coronary intervention, also known as coronary angioplasty, or coronary artery bypass grafting. These procedures help restore blood flow through narrowed or blocked coronary arteries.

People who have sudden cardiac arrest often get a device called an implantable cardioverter defibrillator (ICD). The device is surgically placed under the skin in your chest or abdomen. An ICD uses electric pulses or shocks to help control dangerous arrhythmias.


**WHAT TO DO WHEN SOMEONE HAS A SUDDEN CARDIAC ARREST NEXT TO YOU**
* The first thing to do is ask someone to call an ambulance for emergency
* Open the person’s airway by tilting their head back and lifting their chin.
* Listen and feel for signs of normal breathing. this should be done for about 8 to 10 seconds. Please Do not  confuse gasps for normal breathing. In cases where you’re not sure if the breathing is normal, then act as if it is not normal.
* If the person is unconscious and is not breathing normally or gasping, then such person has a cardiac arrest.
* Before the ambulnce arrive you can buy time by doing cardiopulmonary resuscitation (CPR)

**How To Do Cardiopulmonary Resuscitation (CPR)
1) Start chest compressions.
* Place the heel of one hand in the centre of the person’s chest. Place the heel of your other hand on top of your first hand and interlock your fingers. Press down firmly and smoothly on the chest up to 30 times. Do this at a rate of about 100 to 120
times a minute – that’s about two each second.
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2) Rescue breaths
* After 30 compressions, open the airway again by tilting the head back and lifting the chin, and give two rescue breaths to the person. To do this, pinch the person’s nostrils closed using your index finger and thumb. Take a normal breath and then blow steadily into the person’s mouth. Make sure that no air can leak out and that the chest rises and then falls with each breath. It should take no more than 5 seconds to give the two rescue breaths. Then give another 30 chest compressions and then 2 rescue breaths.
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3)  Continue CPR
* Keep doing the 30 chest compressions followed by 2 rescue breaths until the ambulance crew arrives and takes over, or the person starts to show signs of regaining consciousness, such as coughing, opening their eyes, speaking, or moving purposefully and starts to breathe normally.


**REFERENCES**

1) http://www.heart.org/HEARTORG/Conditions/More/CardiacArrest/Cardiac-Arrest_UCM_002081_SubHomePage.jsp
2) https://medlineplus.gov/cardiacarrest.html
3) www.2minutes.org.uk
4) https://www.nhlbi.nih.gov/health/health-topics/topics/scda/causes