Every day, more than 500 Americans suffer cardiac arrest in the presence of another person, according to the American Heart Association. But in most of those cases, the victims don’t receive cardiopulmonary resuscitation (CPR), and many don’t survive.

Adrian Mosley, administrator of The Johns Hopkins Medicine Office of Community Health, runs a program aimed at teaching hands-only CPR to African-Americans in churches throughout Baltimore.

In hands-only CPR, 911 is called when a person is in cardiac arrest, then rapid chest compressions are delivered until help arrives.

The Johns Hopkins program began in 2011 and paid off right away.

“We had someone from one of our first classes do hands-only CPR on a heart attack victim until paramedics arrived,” Mosley says. “They rushed the patient to a hospital, and that patient survived.”You Gotta Have Heart, along with Faith and Food and Safe in the Salon, is a faith-based initiative that Mosley administers in her role with the Office of Community Health.

“Reaching people in the city’s neighborhoods through their churches is a model that has really worked for us,” Mosley says.

In addition to the technical aspects of hands-only CPR, Mosley’s course addresses barriers to performing an intervention on a person suffering a heart attack.

“There are a number of reasons why folks might not jump in and help,” she says. “Panic, fear of further injuring the person, an aversion to mouth-to-mouth resuscitation. We take on all those topics.”

The program goes beyond instructing participants to perform CPR—it also teaches people to teach CPR. Class sizes range from 20 to as many as 90 participants. Since the program’s inception, nearly 2,500 people have been trained. Participants are given a take home kit with a training DVD for family members and friends.

“The train-the-trainer model is a way to make this more viral,” says Mosley.