Apple Watch fails to record ECG and report atrial fibrillation episodes

The watch fails to record ECG only when i am in atrial fibrillation, yielding "poor recording". It yields a good ECG when heart beating normally.

The watch also fails to report atrial fibrillation episodes when they occur. I am a physician and wanted to get some indication of the length of time in atrial fibrillation, especially when asleep. I

s my watch underperforming or is this common problem?

[Re-Titled by Moderator]

Original Title: Apple watch fails to record ECG when in atrial fibrillation and does not alert that atrial fibrillation occurred.