[dvasdekis]

I personally wonder if some heart attacks have been reclassified as cardiac arrests or other outcomes as our understanding of heart health has advanced?

It's just a thought, I don't have any data to support this. Not sure if anyone has any insight.

[mr_toad]

Seems unlikely, we’ve known the difference for a long time, and the diagnosis versus say cardiogenic shock is pretty straightforward.

The classifications are not mutually exclusive. You can have one without the other, or both together. Given that most cardiac arrests are caused by MCI I’d expect the rates of deaths due to cardiac arrest declining as well.