Apparently, 20 percent of patients who need to wear defibrillators don't actually keep them on at all times -- even if they mean the difference between life and death. So, a group of biomedical engineering students from the Johns Hopkins University designed a new type of wearable defibrillator, which is unobtrusive and comfortable unlike traditional harness designs. The undergrads' version takes on the form of a stretchable, waterproof vest fitted with sensors. Also, instead of using bulky control boxes to monitor the condition of a patient, its sensors are connected to a relatively small smartwatch-like interface.

Doctors typically ask patients to use wearable defibrillators if they've recently had a heart attack or a heart surgery, and they're waiting for a pacemaker implant. The team didn't exactly change the science behind the device, they just make wearable defibrillators a lot more, well, wearable, so that patients won't be tempted to take them off. According to team member Melinda Chen:

We just changed the form of the device. We pursued a 'slip-on and forget' approach to minimize the user's need to maintain and interact with the device.

That means the vest, like any harness defibrillator, detects deadly irregular heart rhythms and shock patients with electricity (200 joules, in particular) to return their heartbeat to normal. In case of a false alarm, patients have 30 seconds to disable the system through its interface. While the the device has already passed preliminary testing using manikins that can mimic a patient's heartbeat, it won't be replacing current designs anytime soon. The team plans to polish the prototype further, and of course, it needs to undergo even more testing before it can start saving lives.