fungus:
If no electricity reaches the heart then you only have to worry about burns.
Incorrect. If it can cook a hot dog... Cooking hot dogs via electrocution | Evil Mad Scientist Laboratories ...it can cook internal organs. And cooked internal organs generally have trouble functioning correctly.
That is exactly how a classmate died from a lightning strike. The person felt sick but otherwise appeared to be OK. They died a few hours later because of the damage done to the hidden bits.