Defibtech LLC of Guilford, Conn., said the recall involves its Lifeline AED and ReviveR AED defibrillators with software versions 2.002 and earlier.

The U.S. Food and Drug Administration said the self-test software might allow a self-test to clear a previously detected low battery condition. If that situation occurs, the device might be unable to deliver a defibrillation shock, which could result in a patient's death.

The company has provided a maintenance procedure that can be used to verify a device's functionality until a software upgrade is developed, allowing the device to remain in service. A copy of that procedure is being mailed to customers and can also be found at Defib Tech.

The software upgrade is expected to be available within 10 weeks.

Defibtech said the recalled units have been distributed to approximately 42,000 end users including: schools, fire emergency service organizations, businesses, health clubs and hospitality companies worldwide.