I've seen them mentioned interchangeably a lot today, so I looked them up just to be sure.
A heart attack is not the same thing as cardiac arrest.
A myocardial infarction, ie a heart attack, is when the heart doesn't get enough blood because something is restricting blood flow. The heart continues to beat, though at less than capacity.
Cardiac arrest is when the heart suddenly stops beating due to malfunction.
Or as the site I went to phrased it:
Heart attack is a circulation problem, cardiac arrest is an electrical one.
Update:
https://twitter.com/tompetty/status/915072929120972801
Official word from his manager on Twitter.
He passed at 8:40 PDT.