Tom Petty Died of Cardiac Arrest. What Does That Mean?

Tom Petty died Monday at age 66 in Los Angeles after entering cardiac arrest. “He suffered cardiac arrest at his home in Malibu in the early hours of this morning and was taken to UCLA Medical Center but could not be revived. He died peacefully at 8:40p.m. PT surrounded by family, his bandmates, and friends,” Petty’s manager said in a statement to PEOPLE.

Cardiac arrest falls under the umbrella of heart disease, which kills around 610,000 Americans every year, according to the U.S. Centers for Disease Control and Prevention. But unlike other forms of heart trouble, cardiac arrest occurs suddenly and often without notice.

Cardiac arrest is caused by an electrical malfunction in the heart that stops the heart from beating. This can be caused by an irregular heartbeat (called an arrhythmia), a heart attack or coronary artery disease. No matter the cause, when the heart stops beating, blood is no longer pumped through the body, which leads to loss of consciousness.

The same factors that put someone at risk for heart disease increase her chances of cardiac arrest. That includes having high blood pressure, high cholesterol or a family history of cardiac arrest and other forms of heart disease.

Without immediate treatment, cardiac arrest is often fatal. About 350,000 cardiac arrests happen each year outside of a hospital setting, and 90% of those people die from the event.

But with emergency medical attention, cardiac arrest often can be reversed. When used within a few minutes, a defibrillator can shock the heart back into a normal rhythm. And now, portable defibrillators, or AEDs, are available in many public spaces (like sports arenas, gyms, malls and restaurants) for bystanders to use. You just follow the instructions and voice prompts.

Hands-only CPR can also help someone in cardiac arrest until an emergency medical team arrives. To give someone in cardiac arrest hands-only CPR, press down firmly on the center of their chest at a rate of about 100 to 120 times per minute.

This article originally appeared on Health.com