What can happen if 0.1 mA of electrical current is applied directly to the heart?

Applying 0.1 mA of electrical current directly to the heart can lead to ventricular fibrillation due to the heart's sensitivity to electrical stimulation. The heart relies on an electrical conduction system to maintain a coordinated rhythm and pump effectively. Even small levels of electrical current can disrupt this normal rhythm, particularly when the current interacts with the cardiac cells that are responsible for initiating and conducting impulses.

Ventricular fibrillation is characterized by chaotic electrical activity in the ventricles, causing them to quiver instead of contracting effectively. This condition is life-threatening, as it prevents the heart from pumping blood to the rest of the body, leading to loss of consciousness and potentially death if not treated quickly.

While electrical currents can cause various effects at different levels, in this instance, the critical aspect is that the threshold for inducing arrhythmias, such as ventricular fibrillation, can be quite low, especially when directly applied to the heart itself. Thus, the risk of such a serious cardiac event underscores the dangers associated with electrical current exposure in medical and emergency settings.