R-R data can be used to calculate various HRV-related metrics, but would also give you "the date and time of every beat". Unfortunately you don't get that data from the Apple Watch, so the point is moot...
Did you have any episodes of tachycardia while wearing the Zio patch? If not, you could do a short ECG recording with the Apple Watch when you sense an episode, and show that to your doctor.
As your sample data appears to confirm, heart rate is sampled only every few minutes (outside of workouts)?
Would definitely be nice if the QS Access app had an option to export data without aggregating it first.