The electrical malfunction of the heart, leading to arrhythmia, can often be avoided if the heart receives an electrical shock from an automatic external defibrillator , or AED.

On Monday, researchers published a list of Toronto businesses and municipal locations that are within 100 meters (328 feet) of areas where large numbers of cardiac arrests have been reported. Their findings appear in the journal Circulation.

The list was compiled based on geographical proximity as well as hours of operation of nearby businesses. Many businesses may already have AEDs, but as study co-author Timothy Chan, a professor of mechanical and industrial engineering at the University of Toronto, puts it, "if that location was closed, it is as if the AED wasn't even there."

Cardiac arrest -- in which the heart suddenly stops beating -- is a leading cause of death among people over the age of 40 in the United States, according to the Sudden Cardiac Arrest Foundation. When the electrical system in the heart stops working, an AED can deliver a life-saving shock, allowing the heart to restart itself.

If the heart stops and no help is available, a person can die within minutes.

But that does not need to be the case. Of the over 350,000 total incidents of cardiac arrest that occur in places other than hospitals, more than 40,000 people could be saved by increasing access to AEDs, according to the foundation.

Chances are that unless you're in a hospital or a school, you wouldn't know exactly where to find this device during an emergency.

"That's the problem," said Dr. Richard Page, chairman of the Department of Medicine at the University of Wisconsin School of Medicine, who provided editorial remarks for the study. "We don't know where the AED might be. Just think, if every Starbucks or Bank of America ATM had an AED and was known for this, then there would be an AED nearby many (cardiac) arrests, and the rescuers would know where to find it."

Frequently, Chan says, people don't know where to find an AED in public, "but if you asked where the closest coffee shop or ATM, most people would know where that is."

"We want to create a relationship between these devices and familiar places such as a coffee shop or ATM," he said.

So why aren't they everywhere? The portable, lightweight devices come equipped with a powerful computer that can detect and analyze rhythms in the heart and decide to restart the muscle if needed. The technology in these devices isn't cheap. "There is a cost," Page said, "and although devices can be under $2,000, the costs would add up, and most would never be used."

Organizations, Chan says, can use this information to identify companies that could use funding assistance to purchase AEDs.

Maximizing coverage, as well as cost, is important to making this a reality. This relationship is one factor researchers have kept in consideration as they attempt to identify the best places to install the devices.

In most cities, ATMs and coffee shops are plentiful and would provide broad coverage for potential instances of cardiac arrest. And as a bonus, almost every ATM is equipped with a video camera and electricity, and is easily recognized and accessible.

Coffee shops were appealing to researchers because they tend to be open later and easy to find. Also on the list of suggested locations are popular fast food restaurants, gas stations and pharmacies.

Extended hours and 24/7 access were crucial for a study on AED availability published by the American Heart Association in 2013 . Researchers found that 68% of cardiac arrests occurred at night and on weekends. And during those times, more than half of the publicly placed devices were inaccessible because the facility that housed them was closed. To someone whose heart has stopped functioning and anyone trying to help, those inaccessible devices are useless.

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Of course, there is no substitute for professional medical attention, but immediate care from an AED administered by an untrained bystander can be the difference between life and death. Although trained non-medical personnel such as police, firefighters, teachers, security guards and other rescuers are the best to operate the devices, anyone can use them. Most come with visual instructions and voice commands to guide the user through pad placement, and the computer does the rest.

According to the American Heart Association, cardiac arrest is often reversible if treated within a few minutes. "It's important because every second matters," Chan said. And a program that takes the information from this research, Page said, "would save lives."

Bank of America and Starbucks did not respond to a request for comment on the report.