A heart defibrillator is a medical device designed to provide a small electrical charge to the human heart in order to resolve arrhythmia and restore the normal rhythm of heart contractions. This device is the most popular treatment for serious medical conditions such as ventricular tachycardia, ventricular fibrillation, and cardiac arrhythmias, all of which interrupt the natural rhythm of the heart and are life threatening conditions if left untreated.
While some defibrillators are used internally and applied directly to the heart, other defibrillators function intravenously or externally. Manual defibrillators are sometimes used as form of resuscitation in cases of cardiac arrest and are often seen in film and television scenes depicting emergency medical care. In recent years, automated external defibrillators (AEDs) that can be used by a layperson with no medical training have begun appearing in many public places. An AED functions by automatically diagnosing the heart rhythm of an individual and prescribing the appropriate medical charge. The AED comes with instructions on how and where to place the accompanying pads on the body and delivers the appropriate jolt of electricity to restore a natural heart beat.
For patients who have a chronic condition that causes serious arrhythmias, an automated internal cardiac defibrillator (AICD) is frequently implanted. An AICD is a device similar to a pacemaker that delivers electrical jolts to the human heart whenever it detects a life-threatening arrhythmia. Many of the newer AICDs available to patients are advanced enough to make the distinction between serious arrhythmias like ventricular tachycardia and less threatening arrhythmias such as atrial fibrillation, allowing the devices to adjust the charge of the administered shock accordingly. However, defective programming and other design faults in some AICDs can occasionally cause the device to start misfiring and administer repeated, unnecessary shocks to the heart. This can result in serious pain and discomfort, and in some cases, this can lead to fatal arrhythmias or cardiac arrest. In fact, emergency medical personnel are now often equipped with a specialized magnetic device that is designed to disable a misfiring internal defibrillator.
In the case of automated external defibrillators, there have many instances in which certain models of these devices have been recalled following repeated reports that the device was defective. In most cases, the problem existed with a fault in the design of the defibrillator that rendered it unable to deliver the necessary electrical charge when it detected a potentially lethal arrhythmia. Sometimes this can occur when there is a problem with the resistors in the defibrillator, in which case the device could not deliver the necessary electrical therapy. In other cases, the failure of a specific relay switch stopped the automated external defibrillator from building up the prescribed charge. Still other faulty automated external defibrillators are unable to wash out interference or background noise in order to correctly diagnose a patient's heart beat, and there have been complaints of other defective components that result in dysfunctional electrocardiography (ECG) analysis.
Because automated external defibrillators are often used by laypeople as a form of emergency first aid, the Food and Drug Administration (FDA) has issued particularly severe warnings to users of these products when there appears to be a problem with a device. The failure of an external defibrillator during a medical emergency may easily result in death or serious injury if emergency medical personnel are unable to reach the affected patient in time.
Although the Cardiac Science Corporation issued a press release in November 2009 calling for the voluntary recall of some models of their automated electronic defibrillators, the FDA followed up the release just days later stating that the company was failing to adequately address the problem and that further action was necessary. The affected defibrillators include CardioVive models 92533, 92532, and 92531, as well as Powerheart models 9390E, 9390A, 9300P, 9300E, 9300D, 9300C, and 9300A. According to the FDA, these Cardiac Science automated electronic defibrillators are affected by a host of defective components, including an inability to recognize pad placement when delivering a charge and incorrect or interrupted electrocardiography. At the time of the initial press release from CardioVive, there were approximately 300,000 Cardiac Science defibrillators being used by the public that may be defective.
In the case of the October 2007 recall of the Sprint Fidelis Defibrillator, manufactured by Minnesota based manufacturer Medtronic Incorporated, the voluntary recall issued by the corporation and the FDA came too late to save the lives of a number of patients. Due to the fracturing in the wire leads of the defibrillators, the device delivered incorrect electrical shocks to patients or failed to work completely, resulting in serious injury or death to many individuals.