Defibrillators: voltage and current?

In 1959 Bernard Lown commenced research into an alternative technique which involved charging of a bank of capacitors to approximately 1000 volts with an energy content of 100-200 joules then delivering the charge through an inductance such as to produce a heavily damped sinusoidal wave of finite duration (~5 milliseconds) to the heart by way of 'paddle' electrodes. The work of Lown was taken to clinical application by engineer Barouh Berkovits with his "cardioverter".

Cardioversion: electric current administered in synchrony with the patient's own QRS complex to stop a dysrhythmia.

Defibrillation: electrical current administered to stop a dysrhythmia, not synchronized with the patient's QRS complex.

Defibrillator Voltage

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Defibrillators: voltage and current?

Having just attended an annual resuscitation training session we were talking about defibrillators and their output. This is always measured in joules i.e 200,300,360 joules but I can't relate to joules as a measure of energy. I know that there is a danger of electric shock from these machines,...

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A continuing current of several milliamps through the heart can be fatal. It requires a certain voltage to generate this current. Current causes muscles to contract strongly, thus immobilizing them. However, AC currents of around 60 Hz (house current frequency) are extremely dangerous because they disrupt the functions of the bundle of His which is the structure in the heart that regulates its beating. This causes ventricular fibrillation, a disorderly squirming instead of regular pumping action. A defibrillator actually delivers a powerful DC current (3-400 watt-seconds in a small fraction of a second) through the heart which completely immobilizes it, in the hope that the bundle of His will take up its normal function again.

The voltages can range from 200 to 1,700 volts

The shock to the chest is also measured in joules. This quantity is a measurement of energy and is different from the voltage. Research shows the energy can start off as low as 40–60 J but can not be greater than 360–400 J.

Approximately 1000 volts has an an energy content of 100-200 joules

Amps is a measure of how much electricity per second.

Volts is a measure of how much pressure they have.

You could have lots of amps with only a little voltage, or

lots of amps with lots of voltage.

You could have lots of voltage with only a few amps, or

lots of voltage with lots of amps.

Or any combination.

Joules are a measure of energy.

1 volt times 1 amp, for 1 second = 1 joule.

1 volt times 1 amp, for 100 seconds = 100 joules.

Volts is a measure of how much pressure they have.

One watt is equal to one joule per secon

So if you go with 1,000 volts, and I went with 200 Joules, and assuming ~5ms discharge (from the wiki that most people copy/pasted) this would give us: 200J * 1200 which just tells us how much would go through in 1 minute. 5 ms * 20 = 100ms or 1 second * 60 gives 60 seconds or 1 minute, that leaves us with 240,000 Joule/minute which gives us 4,000 Volt Amps. Since we know the voltage to be 1,000 that leaves the amperage at 4 amps.

It needs a current of 24 A, a voltage of 5 kV, monophasic, or 2 kV, biphasic and is applied for the time of 10 ms. So the energy is 2000*24*0.01=480 J (which is pretty much according to recommended max of 360 J). From which I guess mentioned vaules are max and ussualy aplied ones are lower.

I think it's about 700, but according to online sources, the voltages can range 200 to 1,700 volts. And these shocks can be repeated up to three times. It can also be measured in joules, the lowest being 40–60 Joules, but must not exceed 360–400 J. Usually 100 to 360 joules are used. Anything above 400 would be detrimental.

Joules To Volts

A joule is a measure of quantity equivalent to an amp second. 300joules is the amount of electricity which flows is the current is 300amps for 1 second - or 1amp for 300 seconds.