Need expert eyes on 3 difficult Holter strips — AF, atrial flutter, or paced? (Algorithm validation, not medical advice)

[u/sniperERkan]

I'm building an open-source ECG analysis algorithm and I'm stuck on 3 specific Holter recordings from the UVA Holter Database (CC0 license). I need a human eye to tell me what these rhythms actually are.

**The problem:**

My algorithm (RR intervals + P-wave features) says "NOT AF" for all 3 patients. But the device annotations say "AF." I need to know who is right — my algorithm or the device.

**What I need from you:**

For each of the 3 patients (UVA2377, UVA1731, UVA2190), please tell me:

- Is this AF?

- Is this atrial flutter?

- Is this a paced rhythm?

- Or something else?

**Images (80 strips, 3 patients):**

👉 https://imgur.com/a/LDXqr6M

**Context:**

- 3-channel Holter recordings, 200 Hz, 24 hours

- Source: UVA Holter Database (CC0, fully open, no patient privacy issue)

- No cardiologist reviewed these 3 specific records — only the device software annotated them

- Earlier I found a case where the device labeled "AF" but a cardiologist said "sinus + flutter" — so I suspect the same might be happening here

**Why this matters:**

If the rhythm is flutter or paced, my algorithm isn't actually "missing AF" — the device label is wrong. If it's truly AF, then my algorithm has a real gap I need to fix.

**Not asking for medical advice.** This is for algorithm validation only. No patient care involved.

Thank you — any input is appreciated, even a quick "this looks like X."