defibrillator


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defibrillator,

device that delivers an electrical shock to the heart in order to stop certain forms of rapid heart rhythm disturbances (arrhythmiasarrhythmia
, disturbance in the rate or rhythm of the heartbeat. Various arrhythmias can be symptoms of serious heart disorders; however, they are usually of no medical significance except in the presence of additional symptoms.
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). The shock changes a fibrillation to an organized rhythm or changes a very rapid and ineffective cardiac rhythm to a slower, more effective one. In a typical hospital defibrillator, voltage stored by the defibrillator pushes electrical current through the chest to deliver a muscle-contracting jolt to the heart; the current is transmitted by means of electrodes or paddles placed on the chest. Automated external defibrillators are now available for use by persons with minimal medical training in emergencies when medical professionals are unavailable, and miniaturization has led to the development of the implanted internal defibrillator (also called an internal cardioverter). In the latter a microcomputer uses an electrode to monitor the heartbeat. Upon detecting a minor arrhythmia, it activates a built-in conventional pacemakerpacemaker, artificial,
device used to stimulate a rhythmic heartbeat by means of electrical impulses. Implanted in the body when the heart's own electrical conduction system (natural pacemaker) does not function normally, the battery-powered device emits impulses that trigger
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 to restabilize the heart's rhythm. If that fails, it delivers a small defibrillating electrical shock to the heart. In an extreme case, it resorts to a far stronger shock to reset the heart rate.

Defibrillator

 

an apparatus designed to eliminate the major impairment of cardiac activity manifested in separate contractions at different times of individual muscle fibers of the cardiac muscle (fibrillation).

In this condition the heart cannot work efficiently. Cardiac activity is not restored spontaneously during fibrillation. The most effective means to stop fibrillation is to feed a single shortterm (0.01 second) electrical impulse created by discharge of the condenser in the defibrillator to the heart muscle (open or through the thorax). Various models of defibrillators (the ID-VEI-1 and ID-66T) have been built in the USSR. The impulses generated by these defibrillators have a less damaging effect on the heart than the apparatus of other systems. A voltage of 1.5-2.5 kilowatts is used for defibrillation on an open heart (during operations), and a voltage of 4-7 kilowatts is used with an unopened thorax.

L. E. MANEVICH

defibrillator

[dē′fib·rə‚lād·ər]
(medicine)
An electronic instrument used for stopping fibrillation during a heart attack by applying controlled electric pulses to the heart muscles.
References in periodicals archive ?
In addition, cardiac resynchronisation therapy defibrillator (CRT-D) is the fastest growing segment and is projected to register a CAGR 5.
SADS UK launched their Big Shock Campaign in 2012 to make defibrillators available in all schools and has the support of the ambulance services and Dame Helen Mirren, who heads the charity's defibrillator leaflet.
Anne Jolly, founder of SADS UK, the Ashley Jolly SAD Trust, said: " Using CPR alone provides a 5% chance of survival but using the defibrillator as well increases the chance of survival to over 50%, this is why SADS UK is so passionate about putting this lifesaving equipment in place.
T-wave testing combined with other tests could reduce unnecessary use of defibrillators by as much as 40 percent, Rosenbaum says.
Within the first six months, the implanted defibrillators had to stabilize potentially fatal abnormal heart rhythms in 61 percent of tachycardia patients taking fish oil, but only 37 percent of tachycardia patients taking the placebo.
Pakizer, who is trained in using the devices, approached supervising Judge Thomas White about getting the defibrillators, and White said it was a good idea.
Establish a centralized management system for the automated external defibrillator.
The ICD segment is further segmented into transvenous implantable cardioverter defibrillators (T-ICDs) and subcutaneous implantable cardioverter defibrillators (S-ICDs).
Overall, only 69 of these volunteers had received a defibrillator.
SANTA CLARITA - Recognizing that an emergency can happen in a heartbeat, the city has contracted with a private company to install 13 defibrillators in several public areas.
An automated external defibrillator is about the size of a laptop computer.