Emergency services dispatched the drone followed by an ambulance when Sven, a retiree who asked for his last name to be withheld, collapsed in early December while shovelling snow outside his home in the western town of Trollhattan.

"Everything from the first 112 call to the drone getting the signal to start and go took about 15-30 seconds and then the whole process took about three and a half minutes," Sven told AFP.

By lucky coincidence a doctor, Mustafa Ali, was driving past. He stopped and began performing CPR as Sven's wife called emergency services, and was there on the spot when the drone arrived with the defibrillator to help restart Sven's heart.

Ali said the drone "really helped" in saving the man's life, as it was used in combination with quick CPR and medicines administered in the ambulance, which arrived minutes later.

"I think it's a really good tool. Especially when it comes to patients that are far away from the nearest hospital," Ali told AFP.

The defibrillator, which gives electric shocks to the heart of a patient in cardiac arrest, was lowered to the ground via a winch, meaning the drone didn't need to land to deliver the device.

The use of medical drones is part of trial run by Everdrone in the area around Gothenburg, and is being developed in collaboration with the Center for Resuscitation Science at medical university Karolinska Institutet, emergency service operation SOS Alarm and regional health authority Region Vastra Gotaland.

Everdrone stated its network can currently reach 200,000 residents in Sweden and "is expected to expand to more locations in Europe during 2022."

In future the unmanned aircraft could be fitted with other medical equipment.

"You could imagine these drones delivering trauma kits in various situations... going to hard to reach islands or other places where it's hard to go at all," Mats Sallstrom, CEO of Everdrone told AFP.

"We started with the defibrillator because it's such a time-critical event" where a drone can really make a difference, he added.