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Introduction
10
Purpose
The defibrillator is a device used for treating cardiac arrhythmias, situations in which
the heart loses the ability of keeping steady heartbeats, blood stops being pumped
and oxygen and nutrients do not get to the organs, starting a degenerative process
known as biological death.
Among the most common cases of cardiorespiratory arrest are ventricular fibrillation
(VF) and ventricular tachycardia (VT), and the most efficient treatment for these
kinds of cardiac dysrhythmia is electrical defibrillation, a technique by which
electrical shocks are applied to the anterior thoracic wall.
Obviously, the success of defibrillation depends on the metabolic conditions of the
myocardium. The more the ventricular fibrillation lasts, the greater the metabolic
deterioration is and, consequently, the fewer chances of the electrical shock
converting it into a steady rhythm.
However, if it lasts shortly, as in the cases of quickly assisted cardiac arrests, shock
response is almost always positive.
Therefore, the most important factor in survival is how fast treatment is delivered.
Ideally, treatment should not be delayed for more than four minutes from the
beginning of the defibrillation.
Principle
Defibrillation is the electrical shock therapy responsible for reversing cardiac arrest
caused by ventricular fibrillation or ventricular tachycardia without a pulse.
The Eazy PRO uses the BIPHASIC SHOCK technology, which is characterized by
a current which is released in a direction and, after a very short time, reverts in the
opposite direction.
During the defibrillation the whole myocardium is briefly depolarized by a strong
positive impulse and a negative one, of adjustable intensity (Biphasic Truncated
Exponential Shock). This impulse is used for eliminating atrial and ventricular
fibrillation and ventricular disturbances.
Compared to monophasic shock, the following advantages can be mentioned
regarding biphasic technology:
• Greater efficiency at ending ventricular fibrillation.
• Lesser damage to the myocardium, through the use of lesser energy intensity,
with attenuation of subsequent myocardial dysfunction.
• Fewer incidence of refibrillation.
