Defibrillator << dee FIHB ruh `lay` tuhr or dee FY bruh `lay` tuhr >> is a medical device used to deliver a brief electrical shock to the heart. The device is used to stop abnormal rhythms during episodes of arrhythmia (irregular heartbeat), such as tachycardia (rapid heartbeat). These conditions can lead to ventricular fibrillation (VF). During VF, the heart fibrillates (quivers) uncontrollably, unable to pump blood. VF occurs when the nerve impulses that regulate the heartbeat fire randomly rather than in rhythm. Without immediate treatment, VF leads rapidly to cardiac arrest and death.
External defibrillators consist of two metal paddles or adhesive pads placed on the chest to deliver a shock from a generator to the heart muscle. Implantable defibrillators are small, battery-powered devices surgically placed under the skin of the abdomen. Tiny wires connected to the heart enable the device to detect abnormal heart rhythms. If such rhythms are detected, the defibrillator generates a brief electrical shock to stop the heart for a split second. This process allows the heart’s normal rhythm to resume.
Automated external defibrillators (AED’s) are available in many public buildings, airplanes, and airports for emergency use. These devices can be used by people who have received only a few hours training. AED’s provide opportunities for rapid treatment for victims of sudden cardiac arrest.
See also Arrhythmia ; Heart (Abnormal heart rhythms) ; Tachycardia .
