Accessing raw ECG and PPG data - Galaxy Watch 4

I would like to know how to access ECG and PPG body sensor data so that i can create a app to determine, for example, blood pressure, SpO2, Heartrate, etc. Can you give me some examples on how to extract this data from Samsung Galaxy Watch 4 Devices?

Now app developers can use public Health APIs. Please see Health Services on Wear OS  |  Android Developers
and examples at
GitHub - android/health-samples

Since Watch4 is Android based questions for it should be asked on an Android Developer Forum.

Hope this helps,

Samsung Developer Relations