Hi,
Sorry for the delayed response. Actualy I don’t have a proper answer. The following are the inputs I can give
The INA332 is connected as a differential ampifier(amplify the voltage difference)
The top OPA336 is connected as an integrator
The down OPA336 is connected as a buffer(keep the voltage same but amplifies current)
The right hand side OPA336 is connected as an active filter
I don’t know anything about the ECG signal and hence can’t explain the purpose of above things.