On Friday, news broke that comedian Ralphie May, 45, had died of cardiac arrest, the same cause of death that claimed rock star Tom Petty, 66, and Playboy founder Hugh Hefner, 91, in the span of a week. 

Here's what you need to know so you can recognize it and treat it in a timely manner.

Comedian Ralphie May, rocker Tom Petty and 'Playboy' founder Hugh Hefner all died of cardiac arrest.

What is cardiac arrest?

 How does it differ from a heart attack and why is the response time a bigger factor when it comes to survival?

According to the American Heart Association, a heart attack is a circulatory problem caused when blood flow to part of the heart is blocked due to arterial blockage or rupture. In the case of cardiac arrest, however, an electrical problem has caused the heart to stop pumping, period. Therefore, no oxygen is getting to the lungs, brain or other organs.

That's why response time is critical in the case of cardiac arrest, says Jonathan Beyer, an emergency physician and EMS medical director in St. Joseph, Mich. 

"Once your heart stops (from cardiac arrest), you are just eating up what oxygen is left in your blood and then you start to starve for oxygen," he explains. Generally speaking, he says, "for every minute you’re down, your chances of neurologically-intact survival go down 10%. So after 10 minutes, your chances are much lower."

What happens in a heart attack?

"A heart attack is a sustained lack of blood supply to a particular part of the heart where the heart muscle starts to die," explains Jorge Plutzky, the director of preventive cardiology at Brigham and Women’s Hospital and Harvard Medical School.

He says that lack of blood supply can be due to blocked arteries, or often in the case of sudden heart attacks in patients with no prior symptoms, the rupture of plaque that has built up inside the arterial wall and is prone to forming blood clots. "And now you've suddenly cut off blood supply."

While most heart attacks do not result in cardiac arrest, they can if the heart's normal rhythm is interrupted as a result.

"When someone's having a heart attack, the part of the heart that's not getting enough oxygen can go into a fatal arrhythmia (irregular rhythm) because the heart muscle cells that help conduct the electricity start dying," Plutzky says.

Editor's note: Parts of this story originally appeared in January 2017.