Q+A: Key facts about cardiac arrest

In this video frame grab from KNBC4 video, the body of pop singer Michael Jackson is loaded into a van to be taken to the Los Angeles County Coroner's office June 25, 2009. Michael Jackson, the child star turned King of Pop who set the world dancing but whose musical genius was overshadowed by a bizarre lifestyle and sex scandals, died on Thursday. He was 50.

(Reuters) - A coroner in Los Angeles has confirmed that pop music legend Michael Jackson died on Thursday after arriving at a hospital in full cardiac arrest.

Cardiac arrest occurs when the heart suddenly stops beating. A cardiac arrest can occur suddenly and without warning.

Here are some facts about cardiac arrest.

WHAT IS CARDIAC ARREST?

Cardiac arrest is an abrupt loss of heart function. Most cardiac arrests that lead to death are caused by abnormal heart rhythms. It can occur when the heart beats too quickly, as in ventricular tachycardia, or when the heartbeat becomes chaotic, as in ventricular fibrillation, or when both occur together.

Cardiac arrest is not a heart attack, which is caused by blockages in blood vessels leading to the heart. People having heart attacks often have crushing chest pain, and far better survival rates.

WHAT CAUSES CARDIAC ARREST?

Drugs, including cocaine and certain amphetamines, can cause cardiac arrest. But the most common underlying reason for cardiac arrest is heart disease. It also has many other causes, including electrocution, drowning, choking and trauma.

Smoking, high cholesterol, diabetes, high blood pressure and stress can increase the risks. Cardiac arrest can also occur without any known cause.

CAN THE HEART BE RESTARTED?

If a bystander witnesses a cardiac arrest, starts cardiopulmonary resuscitation (CPR) and calls emergency medical workers to shock the heart with a defibrillator, people can survive a cardiac arrest.

Each minute without CPR and defibrillation cuts chances of survival by 7 to 10 percent, 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.

Automated external defibrillators, often found in airports and other public places, vastly improve the chances of survival.

Sources: American Heart Association and the American College of Cardiology.

(Compiled by Julie Steenhuysen in Chicago; Editing by Will Dunham)