If someone's heart suddenly stops beating, a quick shock can be a lifesaver.
That's why you see automated external defibrillators, or AEDs, in airports, schools and malls. Even someone with little or no training can use the devices, which only deliver a shock when they sense an abnormal rhythm.
But experienced first-responder or not, whoever is going to help the victim needs to have an AED close by when someone collapses.
Some Canadian researchers wondered are AEDs being put where they're needed most? The short answer is probably not.
Researchers compared the locations of AEDs registered with the local authorities in Toronto with cases of cardiac arrests that weren't related to trauma and that occurred outside hospitals. There were 608 cardiac arrests like that around Toronto during a four and a half year period ending in the middle of 2010.
Turns out that the most likely place to have an AED is a school building — elementary, secondary or university. Nearly three-quarters of those locations had one.
But schools aren't hot spots for cardiac arrests. Over the course of a year, you'd expect one cardiac arrest for every 264 elementary and secondary school locations, for instance.
Where's the action? You'd find one cardiac arrest a year for every two race tracks and casinos. Same ratio for jails. The findings were just published online by the Annals of Emergency Medicine.
Those findings jibe with what's already known. A famous scientific paper from back in 2000 showed that security personnel at Las Vegas casinos trained to use AEDs dramatically improved survival rates among patrons who collapsed from cardiac arrest. Casinos, at first reluctant, embraced AEDs with zeal.
"The safest place in America to suffer sudden cardiac arrest is a casino," Bryan Bledsoe, an ER doctor told The Wall Street Journal in a 2006 story about the dramatic reduction in deaths from cardiac arrest on the Las Vegas Strip.
"We want to turn the entire public setting into a casino," Dr. Steven Brooks, an ER doc at Queens University in Kingston, Ontario, and lead author of the latest study tells Shots. "We can move survival from 10 to 20 percent to 60 to 70 percent, if you're in the perfect setting."
Putting defibrillators where the odds say they'll be needed most would be a good start. Brooks says that good intentions drive the placement of many AEDs in the community. Rare but tragic events on sport fields, for instance, are one reason AEDs are being placed in schools, he says.
Brooks isn't opposed to AEDs in those places. There's an educational benefit, for instance, for children who get used to seeing AEDs and who learn what they do. And the devices can save lives there when cardiac arrests occur.
But he says he'd like to see data drive more decisions in the future. "I'm just saying that if we're looking at the risk of cardiac arrest other places are underserved."