Is there anyway to detect no pulse, whiles the watch is on the user?

The current apple watch series 5 uses photoplethysmography with it's optical heart sensor, right?

And it current supports a range of 30 BPM - 120 BPM.

However, I would like a way to detect if the user is dead/ there heart is not beating at all, do you believe the current physical makeup of the watch has components capable of this? It does not have to specifically relate to using the heart censors.

The ECG would be out of question since the user has to interact with it, so I was focusing mostly on the optical heart sensor.