The effects of electrical passage are generally worse with alternating current (AC) than with direct current (DC).

The current follows the line of least resistance within the body. Skin has a high resistance when dry, followed by bone, muscle, blood vessel and nerve. The higher the resistance, the greater the damage produced.

The points at which the electrical energy actually enters and leaves the body are marked by burns: the entrance and exit wounds.

Alternating current in the domestic setting produces entrance and exit wounds of approximately the same size.

In an industrial environment, direct current is the most common cause of injury and produces a small entrance wound and a much larger exit wound.

At the time of injury, ventricular fibrillation may have been precipitated by the electric shock.

The greatest threats to life following electrical injury are a consequence of tissue damage, resulting in the release into the circulation of potassium and a product of muscle breakdown, myoglobin. These may cause cardiac arrhythmias and renal failure respectively.

Remember the possibility of secondary blunt injury, which may have resulted from the victim being thrown by the electrical contact. In any unconscious patient, therefore, cervical spine injury must be assumed and closed head injury suspected.

Alternating current is generally more dangerous than direct current at any given voltage because it is more likely to induce ventricular fibrillation.