External biphasic defibrillators, monitor/defibrillators and automated external defibrillators (AEDs) used to provide cardioversion therapy to patients are being investigated by the Food and Drug Administration following reports that the devices designed to deliver 200 J (joules) were ineffective during use.
Defibrillators are devices used by emergency or medical personnel or by others who have completed CPR AED training courses to treat adults in cardiac arrest. The devices analyze an unconscious patient’s heart rhythms and automatically delivers an electric shock to the heart if needed to restore a normal heart rhythm.
To date, the FDA has received 14 reports in which 200 J biphasic defibrillators were ineffective in providing cardioversion therapy to patients, whereas a subsequent shock from a different 360 J biphasic defibrillator resulted in immediate cardioversion. The majority of events occurred during attempts at cardioversion of atrial fibrillation, but there was at least one instance with defibrillation of a ventricular arrhythmia as well.
The findings spurred the FDA investigation, but the agency is encouraging health care providers to follow the American Heart Association’s guidelines/algorithms for treatment of cardiac arrhythmias, to follow manufacturers’ instructions for using defibrillators, and not change current clinical practice. The FDA is continuing its evaluation of the devices and will determine whether any activities are advised. Health care providers who suspect a problem with a defibrillator, such as a situation where a patient received shocks from multiple devices, the problem should be reported to the FDA’s MedWatch Safety Information and Adverse Event Reporting Program at www.fda.gov/MedWatch/report.htm.