What causes death by electrocution? I mean what exactly happens to the body physically to cause death.?

What makes a person die by electrocution, what are the physical and chemical changes that happen to the body on being subjected to high voltage?
Answers:
Just to clear this up: It is NOT the voltage that kills you - it is the amount of CURRENT flowing through you.

eg. the static electricity on a colour TV screen is around 30Kv - but virtually no current. Yes, Thirty THOUSAND volts.

Death by electrocution occurs when the current flowing through your body does several things:

Heart failure - when a current over 6mA (6 thousandths of an Amp) flows through / across the heart causing the heart to 'fibrillate' or interrupt the normal rhythm (just quivers).

Burns - when the current overcomes the bodies naturally (dry) high surface resistance either through moisture or through because of very high potentials (voltages) with high currents available. The electricity will burn MAINLY the entry & exit points, as fluid is released from the wound site, the currents can increase. It can cause immediate flash boiling of all fluids in the immediate vicinity.

Nerve damage / shock - electrolyte imbalance as an after effect of high voltage shocks. After suffering fright or actual bodily harm. Includes memory loss, slow or slurred speech, heart and breathing irregularities.
It causes all the nerves in your body to depolarize at once and not repolarize. If the nerves stop working then the muscles stop working. If the muscles stop working, then the heart stops beating and you stop breathing. You also experience burns. I don't know what happens to the brain but it can't be good. The heart and lungs will be enough to kill you.
it causes your heart to stop.
Heart failure
Heart failure and lack of air
Every working part in your body seizes. And the electricity fries your body inside.
It is gross, just gross!
The first shock runs for up to one minute and normally destroys the brain and central nervous system. It also causes complete paralysis due to every muscle in the body contracting and staying contracted whilst the current is flowing. This makes heartbeat and respiration impossible. The second shock continues the process to ensure the heartbeat does not resume. The prisoner is supposed to be rendered unconscious in 1/240th of a second.
After electrocution, the body temperature rises to about 138oF and is initially too hot to touch. Heating destroys the body's proteins and "bakes" the organs.
Physical reactions include heaving chest, gurgles, foaming at the mouth, bloody sweat, burning of the hair and skin, and release of faeces.
The body has to be allowed to cool before an autopsy can be performed.
According to Robert H. Kirschner, the deputy chief medical examiner of Cook County, Illinois, "The brain appears cooked in most cases."
According to Judge Brennan, the prisoner's eyeballs sometimes pop out and rest on his cheeks. The prisoner often defecates, urinates, vomits blood and drool. The body turns bright red as its temperature rises, and the prisoner's flesh swells and his skin stretches to the point of breaking. Sometimes the prisoner catches on fire, particularly if he perspires excessively. Witnesses hear a loud and sustained sound like bacon frying, and the sickly sweet smell of burning flesh permeates the chamber.
The current flowing through the body, especially if contact points are in line with the heart, cause fibrilation and upset the hearts electrical signals, causing it to stop, Tissue damage can occur depending on voltage and current levels, this damage is usually between the points of contact. People have survived high voltages of over 10000v, others have died at 200 volts. All depends on the current and how long it flows for. Really high voltages simply fry you.

Just saw the post above! I didn't think you were asking about execution,? just electrocution.