Here’s some not-so shocking news: A person suffering from cardiac arrest is twice as likely to survive the attack if there is a defibrillator… and a person trained to use it nearby. That was the finding of the U.S. Food and Drug Administration after an initiative that put automated defibrillators into the hands of ordinary volunteers in office buildings and shopping malls.

But recently the FDA discovered a major flaw in its plan to save lives: Too many of the devices are malfunctioning. In the past five years, the FDA’s Center for Devices and Radiological Health has received more than twenty-eight thousand reports of defibrillators failing. Manufacturers also issued sixty-eight recalls involving hundreds of thousands of defibrillators.

In response, the FDA has developed a program aimed at helping companies make safer, more reliable devices. On its Web site, the agency lists some common design flaws. For example, one manufacturer designed its voltage monitoring circuit to draw power from the same source it was intended to monitor. This caused a momentary drop in power, making the device unable to deliver a shock, which may have led to a patient’s death. In other cases, manufacturers purchased components for defibrillators that did not meet required specifications.

The stakes are high: Nearly a quarter-million Americans die from cardiac arrest each year. Multiple studies have shown that a victim is far more likely to survive if a defibrillator is used soon after the attack. That’s why they have become standard equipment at many shopping centers, entertainment venues and sports facilities. In fact, the FDA is hoping to encourage more businesses to invest in the devices — as long as they are properly working.