Reader Question

Hi all
Got this readers question. It’s one of those things not taught often!
Are you a cardiac physicology guru. Can you answer in 100 words?
Leave your explanation on the comments please
Casey
Here’s the Q-
: Hi, I am confused by the Units we use when Defibrillating and Trans-cutaneous Pacing.
When we Defibrilate we dial to 200J (Not Amps). (Cardiovert=100J)
When we Pace Transcutaneously we dial using Amps (Not Joules).
Yet both deliver a ‘shock’ from the same device which causes Skeletal Muscle Contraction.
Why dont they both use the same Unit(Joule or Amp)?
What Amp roughly does 200J deliver?
How many Joules roughly in a 80Amp pacing ‘shock’?
And in both cases, what is the voltage and time length of discharge? Fixed or Variable?

To refresh anyone who is more than 1 day out of year 12 Physics: Voltage =Amps(Current ie Vol/time) x Resistance
Watts (Power) =Joules/1second=VoltagexAmps
1 Joule=1Voltx1Ampx1Second

(Out of interest does anyone therefore know the Units a Implantable Cardiac device uses given it delivers directly to the Myocardium of interest?)

Thanks!

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