system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Can heart attacks happen randomly or are they always brought on by something?

And do they tend to be reoccurring?
gpt
Heart attacks, like all things, have a cause. A heart attack may appear random, but that's simply because you didn't see it coming. Heart attacks can be reoccurring, or they can be a once in a lifetime thing, it depends on numerous factors.