A few hours ago, pop star Michael Jackson died at age 50 after suffering a cardiac arrest. As you’ll read in this article, there are many possible causes behind a cardiac arrest, and at the moment the exact cause behind Jackson’s isn’t clear. You can subscribe to our RSS or eMail feed to get updates on the situation, or follow us on Twitter, where relevant news will be published.

Danger level: High

What is it?

Sudden cardiac arrest (or sudden cardiac death) occurs when the heart suddenly stops beating.

Who gets it?

About 325,000 people in the United States die each year of a sudden cardiac arrest (more than lung cancer, breast cancer, or AIDS). Some studies claim that it is more common in people of African American origin than in white people.

Men have a higher chance of having a sudden cardiac arrest (3 times as much as women).

Since, as you’ll see ahead, the main reason behind a sudden cardiac arrest is a problem in the coronary arteries of the heart, the age when people die of it is about the same age when people have heart attacks – it is most common between ages 45-75.

Michael Jackson. Photo by Richard Pflaume.

There are a few risk factors which can put you at risk of having a cardiac arrest:

1. The same risk factors which put you at risk of having a heart attack (You can read about them here).
2. If you had a previous episode of a cardiac arrest, or someone in your family had it
3. If you or someone close in your family have had a history of other types of heart disease, such as heart rhythm problems, congenital heart defects, heart failure or cardiomyopathy.
4. If you use illegal drugs such as cocaine or amphetamines
5. If you get electrocuted or get hit by lightning
6. If you immerse yourself in cold water

What causes it?

There are many things which can cause a cardiac arrest. The common thing is that they all can lead to an abnormality in the rhythm of your heart, which causes your heart to stop. Our heart has to beat at a certain rhythm in order for it to pass blood to our body. If it beats too fast, too slow, or irregularly, it can lead to problems with the heart’s function, and to a cardiac arrest.

The most common type of heart rhythm problem causing a cardiac arrest is called a ventricular fibrillation – in which the ventricles of your heart beat at an extremely rapid rate. This leads to those chambers not being able to fill properly, and so they can’t pump blood to important organs in the body, such as the brain and other important organs. If it’s not reversed within 4-5 minutes, death can occur.

In healthy people, usually cardiac arrest doesn’t develop. It needs some sort of trigger, such as:

1. An electrical shock
2. The use of illegal drugs
3. An injury to the chest
4. The most common situation – A pre-existing heart condition. This can include:
   a. People with atherosclerosis – more than 80% of cardiac arrests occur because of a disease in the heart’s arteries.
   b. Heart attack – A hear attack can trigger a ventricular fibrillation, causing a cardiac arrest.
   c. Cardiomyopathy – This means an enlarged heart. It can lead to a sudden death – most cases of young athletes dying suddenly occur as a result of this.
   d. A problem in the heart’s valves.
   e. A congenital heart disease – This means a problem you were born with.
   f. Problems with the conducting system of the heart – This is the system responsible for the regular beats of the heart.

How is it treated?

The heart can be “restarted” after it stops. This can be done by performing a CPR (cardiopulmonary resuscitation) and shocking the heart with a defibrillator. The CPR helps to maintain a flow of oxygen-rich blood to the body’s vital organs. The defibrillator stops the rhythm problem and “restarts” the heart.

A defibrillator. Photo by Ernstl.

It’s important to know that each minute without CPR and defibrillation cuts chances of survival by 7-10%, and few resuscitation attempts succeed after 10 minutes. In the United States, more than 95 percent of people who suffer cardiac arrest die before reaching a hospital.

Since there is no way to know if you are bound to have a cardiac arrest, it’s important to have regular doctor checkups, including checking your heart’s condition. Other measures that can help include:

1. Quit smoking
2. Eat a balanced diet
3. Keep physically active

In some cases (such as a heart condition) medications can help. See your doctor about that.

For some people, an implantable cardioverter-defibrillator (ICD) can be transplanted under the skin. It works like a normal defibrillator (the one in the picture above), but can prevent the cardiac arrest from occurring in the first place. It is usually given to people at high risk of developing a cardiac arrest.

What next?

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