Contrary to expectations, crowdsourcing, social media, and Twitter blasts didn't help win the MyHeartMap Challenge, the University of Pennsylvania's project to map the locations of automated external defibrillators (AEDs) - portable gizmos that can save cardiac arrest victims.

The winners, Frankford High School athletic director Jack Creighton and information technology analyst Jennifer Yuan, relied on old-fashioned shoe leather. Each found more than 400 AEDs, and Penn announced Thursday afternoon that each will receive a grand prize of $9,000.

The two winners discovered that walking into a building, finding out whether there's an AED, and snapping a photo of it is tremendously difficult. Often, the AED hunters were confronted by blank stares, red tape, or mistrust and even fear.

"Sometimes we'd go out for three or four hours and not be allowed to take a single picture," Creighton said of his team, made up of his wife and daughter. "At Independence National Park, they said, 'Oh, we can't show you where the AEDs are. National security.' At the sewage treatment plant, they said, 'We'll have to check with our lawyers.' They never called me back."

That was just one surprising outcome of Penn's contest.

Another surprise was that the original estimate of 5,000 public-access AEDs was way too high. A more accurate guess, Penn researchers now say, is 2,500. And contestants identified locations for 1,500 of them. (Many AEDs are in inaccessible places such as prisons and ambulances.)

AEDs have been proliferating since the 1990s, when regulators and health associations endorsed the use of the devices by laypeople.

An AED can detect whether a heart has stopped because of an arrhythmia, then deliver a therapeutic electric shock. It will not fire if a shock won't help, and even an untrained bystander can follow the step-by-step audio instructions.

With 300,000 cardiac arrests each year in the United States, the technology has been a public health boon.

However, no one maintains a comprehensive list of AED locations. And quality control and oversight of the devices varies. Some businesses fear they'd be held liable if their AED failed.

MyHeartMap aims to reduce these obstacles, starting in Philadelphia, then expanding beyond.

Organizers are now verifying the locations of the 1,500 AEDs submitted through the contest website.

The data will be used to create an interactive AED registry that will become part of the city's 911 call system and be available through a smartphone app. Also, a map showing the AEDS will be posted on philly.com/health.

Contact Marie McCullough at 215-854-2720 or mmccullough@phillynews.com.