Experimental Device Warns of Heart Attack

Implantable AngelMed Guardian notifies patients of heart attack

(RxWiki News) An experimental implantable medical device could help heart patients seek treatment sooner by warning them if they suffer a suspected heart attack.

The device, which is in clinical trials but is not yet approved by the U.S. Food and Drug Administration, would offer two alarm types.

The urgent alarm indicates a patient could be having a heart attack and asks them to call 9-1-1, while a low-priority alarm indicates a condition has been detected that requires a doctor visit within 48 hours.

"Call 9-1-1 immediately if you experience heart attack symptoms."

Mary Carol Day, a partner with NewDay Solutions and author of the research studying the benefits of the AngelMed Guardian, noted that the device has two major advantages. The first is that it can't be left at home as is the case with portable devices. In addition, she said the device is equipped with a vibrotactile alarm that combines vibrations, audible tones and visual warnings.

This could be especially beneficial to elderly patients with hearing loss, for those wearing heavy clothing, or individuals who can't hear an alarm because they are in a noisy environment.

The implantable device is about the size of a pacemaker and is placed in the upper left chest. Patients also receive an external device, similar to a pager, that vibrates, sounds alarms and flashes red or yellow warning lights.

Researchers hope the service could ensure patients  with heart attack symptoms receive treatment sooner because, on average, it takes patients three hours after the onset of a heart attack to arrive at the hospital. About 30 percent of U.S. heart attack patients die without seeking medical attention.

Once the ongoing clinical trials have been completed, about 1,000 U.S. heart patients at 50 medical centers will have received the device. The device is primarily geared toward high-risk heart patients with coronary artery disease. The potential price tag of the Guardian pending FDA approval is unknown.

During the recent trio of studies 64 patients over the age of 55 had the device pressed against their skin instead of implanted so that researchers could study the effectiveness of the alert system.

Investigators have focused recent study on the combination of alert modes, finding in a series of studies that older adults were able to tell the difference between the low- and high-priority alarms and respond appropriately. The seniors testing the devices also reported they liked the vibrating alarms, and the redundancy of the warnings.

The vibrotactile alarms have been used to warn hospital clinicians of an emergency, but there has previously been little research into whether patients would positively respond to that type of alarm system when incorporated into a self-monitoring device.

Certain implantable heart defibrillators for patients with arrhythmias have auditory alarms, but some patients, many who are elderly, have trouble hearing the alarms.

“If the Guardian is approved for sale by the FDA, it might be extended in ways that will change the way the patient interacts with the system as a whole," Day said.

"This would require more research and simulated-use studies to refine and validate the new interactions between the patient and the system.”

The study was published in the April issue of journal Ergonomics in Design.

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Review Date: 
April 13, 2012