The Defibrilators carried by ambulances are actually quite clever - first they look for the electrical signal for a pulse and will not fire unless there really is a patient connected and a irregular rythm is detected that needs correction,

Then a large capacitor is charged, much in the manner of a camera flash gun, and discharged into the patient. The intention here  is to bring all the muscles to a dead stop, so it restarts with the correct timing.

The public ones are even better, and a 'Dalek voice'  will talk a complete novice through the procedure so no real skill other than English and staying calm is needed.

Having looked into this for a previous project, and being taught  1st aid both for work and for Scouts, the energies discharged are eye watering and far above what we would consider safe for things like electric fences etc.

Soberingly, despite what occurs on films etc,  even with a defib machine,  success is far from  guaranteed  (50-70% from a heart attack in the street) but it is much higher than CPR alone ( which sadly has less than 10% survival rate).

Chris's process sounds a lot more safe and controlled, but according to the NHS at least artrial fibrillation is generally not life threatening, many people live more or less normal lives with this condition for some time before recognition  and treatment.

Mike

The Defibrilators carried by ambulances are actually quite clever - first they look for the electrical signal for a pulse and will not fire unless there really is a patient connected and a irregular rythm is detected that needs correction,

Then a large capacitor is charged, much in the manner of a camera flash gun, and discharged into the patient. The intention here  is to bring all the muscles to a dead stop, so it restarts with the correct timing.

The public ones are even better, and a 'Dalek voice'  will talk a complete novice through the procedure so no real skill other than English and staying calm is needed.

Having looked into this for a previous project, and being taught  1st aid both for work and for Scouts, the energies discharged are eye watering and far above what we would consider safe for things like electric fences etc.

Soberingly, despite what occurs on films etc,  even with a defib machine,  success is far from  guaranteed  (50-70% from a heart attack in the street) but it is much higher than CPR alone ( which sadly has less than 10% survival rate).

Chris's process sounds a lot more safe and controlled, but according to the NHS at least artrial fibrillation is generally not life threatening, many people live more or less normal lives with this condition for some time before recognition  and treatment.

Mike