Can an Apple Watch 7 detect a heart attack?

This is what Apple says:

• Apple Watch cannot detect heart attacks. If you ever experience chest pain, pressure, tightness, or what you think is a heart attack, call emergency services immediately. 

Some folks think that the technology is there, and that it is conceivable that the watch could do this. But it may be some time before detection algorithms would be so reliable that Apple would want the responsibility of possible errors.

So, "No."