Other runners saved Bill Amirault after he collapsed at the end of a half marathon. He wanted to know who they were, so he tracked them down on Facebook.

The crowd cheered as Bill Amirault neared the finish line of the Key West Half Marathon in Florida.

That joy, however, was short-lived.

Amirault started to feel faint and had tunnel vision, so he slowed to walk. Then, he collapsed.

Fellow runners and bystanders rushed to him.

The first three people to reach him were all nurses. They directed someone to call 911 and started CPR. They saved Amirault’s life.

Read more: Mom uses CPR to save son on soccer field »

A longtime runner, Amirault had aligned the 13.1-mile race in January with a business meeting.

It was his sixth half marathon.

“I trained, but not as much as I should have,” he said. “I didn’t think I would finish.”

The Colorado resident had never fainted before.

“I remember lying down on the ground, then everything went black,” Amirault, 45, recalled.

Amy Smythe of Maryland had finished the half marathon and was waiting for friends when she saw Amirault head to the curb. She thought, “Don’t stop, you’re almost there.”

Then, she saw him on the ground.

As a cardiology nurse, Smythe knew to rub his chest, but there was no response.

Runner Lisa Vos, a delivery nurse at a hospital in Illinois, couldn’t find Amirault pulse, so she started mouth-to-mouth resuscitation while Robbie Ladd — at the race to cheer on his wife — and Smythe took turns performing chest compressions.

“Bill was purple and had labored breathing,” said Ladd, a nurse anesthetist from Florida who kept Amirault’s airway open until emergency help arrived.

Emergency medical technicians used an automated external defibrillator, or AED, to shock Amirault’s heart back into a normal rhythm.

Read more: How to perform CPR »

American Heart Association guidelines for CPR recommend that anyone who sees an adult collapse should call 911 and provide chest compressions at a rate of 100 to 120 compressions per minute.

Guidelines also recommend rescue breaths during CPR by people willing and able to deliver them.

“Time stood still,” recalled Vos, a former American Heart Association (AHA) CPR instructor. “I was kneeling at his head, praying.”

Amirault’s heart suddenly stopped due to ventricular fibrillation, an electrical malfunction that impeded blood flow and caused a dangerously irregular heart rhythm. That caused sudden cardiac arrest.

More than 350,000 Americans each year suffer an out-of-hospital cardiac arrest.

Unlike about 90 percent of those people, Amirault survived mainly because of two factors: quick CPR and a fast emergency response.

Amirault was transported to Mount Sinai Medical Center in Miami for tests, but doctors couldn’t pinpoint the cause.

Doctors implanted a defibrillator in Amirault’s chest to shock his heart should a life-threatening rhythm ever occur again.

Read more: Most Americans are afraid to perform CPR »

In the hospital, Bill learned about the “angels” who performed CPR.

From his hospital bed, he recorded a video thanking them.

He shared it on Facebook. Within a few hours, it went viral.

The video received more than 1.7 million views. That’s how Vos, Smythe and Ladd discovered Amirault had survived.

Producers of Harry Connick Jr.’s talk show heard about Amirault’s story and invited him and the three nurses to appear for a reunion. The episode aired April 5.

They all want to spread a key message: Learn CPR and don’t be afraid to help others in need.

“I want to reassure people it doesn’t hurt to try to help,” Vos said. “CPR can save lives.”

In fact, bystander CPR, especially if done within the first few minutes of a cardiac arrest, can double or triple the chance of survival.

AHA-authorized training centers offer online and instructor-led CPR courses. AHA also offers 20-minute, at-home CPR Anytime training kits.

The experience has changed Amirault’s outlook on life.

The entire family — Amirault, his wife, Becky, and two daughters — received CPR and AED training.

Amirault also began volunteering for the AHA, sharing his story and supporting local events, such as Heart Walks.

And he’s leaving his software engineering job to focus on Move4Charity Inc., a nonprofit he started for CPR/AED awareness and fundraising.

“As far as I’m concerned, this is bonus time that I’m still here,” he said. “I decided I wanted to pay it forward.”

The original story was published on American Heart Association News.