A shock of what magnitude lasting 0.03 seconds may cause heart fibrillation?

The correct answer pertains to the threshold at which electrical current can disrupt the normal rhythm of the heart and potentially cause fibrillation. Research in electrophysiology indicates that a current of approximately 100 mA can induce ventricular fibrillation if applied to the chest for a sufficiently brief duration, such as 0.03 seconds. At this magnitude, the electrical stimulation can interfere with the heart's electrical conduction system, leading to chaotic heartbeats that are characteristic of fibrillation.

In medical considerations, currents above this threshold are acknowledged as potentially lethal, particularly with such a short exposure time. Values below this threshold, while still dangerous, may not have the same immediate severity to produce fibrillation as effectively. Thus, it's essential to recognize 100 mA as the level where there is a significantly heightened risk for such serious cardiac effects.