The minimum macroshock current required to elicit ventricular fibrillation is:

The minimum macroshock current required to elicit ventricular fibrillation is:

• A. 1 mA
• B. 10 mA
• C. 100 mA
• D. 500 mA

Answer: (C)

When electrical current passes through the chest at mains frequency, it can disrupt the heart’s electrical activity and trigger ventricular fibrillation. There is a threshold current at which this becomes likely, and at 50–60 Hz the minimum macroshock current known to reliably induce VF is about 100 mA. Currents much smaller, around 1 mA, are usually only perceptible as a tingling sensation, and around 10 mA cause mild muscle effects but not VF. Higher currents increase risk, but the value around 100 mA represents the point at which VF can begin to occur, making it the best answer.

When electrical current passes through the chest at mains frequency, it can disrupt the heart’s electrical activity and trigger ventricular fibrillation. There is a threshold current at which this becomes likely, and at 50–60 Hz the minimum macroshock current known to reliably induce VF is about 100 mA. Currents much smaller, around 1 mA, are usually only perceptible as a tingling sensation, and around 10 mA cause mild muscle effects but not VF. Higher currents increase risk, but the value around 100 mA represents the point at which VF can begin to occur, making it the best answer.