Federal health regulators are warning the public not to use certain defibrillators recalled by Philips Healthcare because the heart-shocking devices may fail to operate in emergency situations.

Philips recalled three models of its HeartStart devices in September due to an electrical malfunction. The recall affects about 700,000 defibrillators sold between 2005 and 2012.

The defibrillators are used by emergency responders and others to restore normal heart function in people suffering a heart attack. The FDA says the electrical problem with the devices could cause them to fail to deliver a life-saving shock.

Customers who have received the devices can contact Philips to receive a new replacement at 1-800-263-3342.

(AP)