More than 30% of the one million heart attack victims in the United States each year die before seeking medical attention. Although widespread education campaigns describe the warning signs of a heart attack, the average time from the onset of symptoms to arrival at the hospital has remained at 3 hours for more than 10 years. In their upcoming Ergonomics in Design article, "'This is your heart speaking. Call 911,'" authors Mary Carol Day and Christopher Young study the benefits of the AngelMed Guardian-, an implantable medical device currently undergoing clinical trials that alerts users about a potential heart attack through a combination of vibrations, audible tones, and visual warnings.
What makes the device distinctive is this combination of alert modes. Although vibrotactile (vibrating) alarms are sometimes used to warn medical personnel in operating rooms or ICUs of an emergency, very little research has focused on their potential as a self-monitoring device for patients. Auditory alarms are provided with selected implantable heart defibrillators, but research indicates that some patients -- particularly the elderly -- are unable to hear the alarms.
"A vibrotactile alarm provided by the implanted device has two major advantages," says Day. "First, the implanted device can't be left behind like a portable device. 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."