“Can a healthy person have cardiac arrest?”

The simple answer to this is YES. But is somewhat complex. A healthy person should not have a cardiac arrest ”just because”. However, there are situations when a person can have it. Examples are, with the use of drugs (ie: cocaine, heroin, synthetic drugs), or if the person receives a really hard punch over the chest at a specific time interval during the cardiac cycle. For the later you can search under ”commotio cordis”.