If you want all-day ECG then you can't have it. If you want to use Sense wrist sensor for medical purpose then it isn't recommended. Wrist sensors have not enough accuracy for such a purpose. Also, I don't think you can get such monitoring out of Sense. All-day HR uses longer intervals and data is being smoothed. It is more like approximation of HR.
For all-day monitoring you may get chest strap which gives an output closer to ECG. As far as I am aware, PolarH10 strap has been granted medical grade in some countries (something to check, don't trust my word only on this). It may be inconvenient to wear it but if it's only for 24 hours then probably you could live with it. There are apps delivering medical analysis (although, probably not cheap).
