Washington: A medical implant can warn users about a potential heart attack through a combination of vibrations, tones and visual signs and save lives, says a study. Named AngelMed Guardian, the device is currently undergoing clinical evaluation, reported study co-authors Mary Carol Day and Christopher Young from the Human Factors and Ergonomics Society (HFES), Santa Monica, CA, US.

More than 30 percent of one million heart attack victims in the US die every year before seeking medical attention. The average time from the onset of symptoms to arrival at the hospital has remained at three hours for more than 10 years, the journal Ergonomics in Design reported. What makes the device distinctive is a combination of alert modes. Although vibrating alarms are sometimes used to warn surgeons in operating rooms or ICUs of an emergency, very little research has focused on their potential as a self-monitoring device for patients.

"A vibrotactile (vibrating) alarm provided by the implanted device has two major advantages," said Day. "First, the implanted device can't be left behind like a portable device," said Day, according to a university statement. "

Second, a vibrotactile alarm from the implanted device is more likely to be felt than an auditory alarm is to be heard because, for example, the patient may be wearing heavy clothing, has hearing loss or is in a noisy environment," added Day. The device offers two levels of alarm urgency: A high-priority alarm indicates that the patient may be having a heart attack and should call 911, and a low-priority alarms indicates that a condition has been detected that requires a doctor's visit within 48 hours.

The alarms are provided by an implanted medical device, similar in size to a pacemaker, that is placed in the upper left chest, plus an external device, similar to a pager, that emits an auditory alarm and flashes a red or yellow warning light. "If the Guardian is approved for sale by the FDA (Food and Drug Administration), it might be extended in ways that will change the way the patient interacts with the system as a whole," Day concluded.