+1 973 704 3459
+91 770 380 1355
MettleSense Shield · Beta v2.0 · Cardiologist reviewed
The full 9-condition arrhythmia classifier from the ECG clinical reference — the same mandatory sequence used in clinical ECG review. Upload your Polar H10 or Apple Watch PDF. Get a verdict in seconds.
Shield runs all 9 checks in Table IV's mandatory order — the same sequence used in clinical ECG review. A condition is only cleared after every prior condition is ruled out.
HR >150 · CV <0.05 · Mandatory first check
Polar "??? ms" fingerprint · RMSSD >200 + HR >100 · CV >0.40
RR pause >3000 ms · Golden Rule: HR >20 cannot be asystole
HR 250–350 · CV <0.03 · OR · HR 120–160 · CV <0.02
HR >150 · CV <0.10 · Not VTach · Not AFlutter
CV >0.15 · SampEn >0.5 · ≥10 RR intervals
QTc >500 ms · Bazett formula + Boudoulas QT estimate
Athlete: <35 bpm · General: <60 bpm or >100 bpm
Cardiac clearance — all 8 conditions ruled out
Shield computes all five. CV(RR) and SampEn catch AFib signatures before simpler tools can — using non-linear chaos analysis calibrated to athlete baselines, not population norms.
Beat-to-beat parasympathetic tone. Your primary recovery readout. The metric every wearable shows — but only the beginning.
Total autonomic load. Overall HRV picture — sympathetic and parasympathetic combined.
Parasympathetic activity percentage. The easiest metric to interpret — percentage of beat pairs differing by >50 ms.
Rhythm irregularity index. AFib and AFlutter leave distinct signatures here that RMSSD alone misses.
Non-linear chaos index (m=2, r=0.2·SDNN). Catches AFib before simpler tools can. The metric clinical ECG systems use that consumer wearables don't compute at all.
Pan-Tompkins is the gold-standard 5-stage R-peak detection algorithm used in clinical ECG systems. Shield runs it entirely client-side — from raw Polar H10 CSV or Apple Watch export. No server. No API. 100% of your cardiac data stays on your device.
HR 51 bpm · RMSSD 47.8 ms · Normal Sinus Rhythm. Every metric live from the uploaded session.
Recovery score runs 0–100 when cardiac status is clear. The moment any arrhythmia flag fires — Shield suppresses recovery to N/A. No score. No reassurance. Just the finding that needs attention.
Workout recommendations — Running, HIIT, Cardio, Strength — appear only when the Athlete profile is active, all 9 classifier checks are clear, and recovery is computed and valid.
HR, RMSSD, SDNN, pNN50, CV(RR), SampEn, Recovery score, rhythm classification, dual-source confirmation, ICD-10 alert — all computed from a single uploaded PDF. No manual entry.
| Device | Format | What Shield extracts |
|---|---|---|
| Polar H10 | PDF (ECG & HRV Insights app) | BPM + RMSSD per page · "??? ms" VFib fingerprint |
| Apple Watch | PDF (30-sec ECG strips) | BPM + device classification + HR=0 auto-correction |
| Any ECG device | Raw CSV (Polar Sensor Logger) | Pan-Tompkins R-peak detection → real RR intervals |
Holter-capable: upload multiple sessions. Shield tracks RMSSD trend and athlete baseline over time.
A resting HR of 38 bpm is normal for an endurance athlete. Shield won't flag it as pathological. Toggle Athlete / General in the header — watch thresholds shift in real time.
| Case | Input | Expected | Result |
|---|---|---|---|
| VFib | Synthetic CSV | VFib flag + recovery suppressed | PASS |
| AFib | Polar H10 PDF | AFib + dual confirmation | PASS |
| SVT / VTach | Apple Watch PDF | SVT or VTach + dual confirmation | PASS |
| Athlete Sinus | Real Apple Watch PDF | Cardiac clearance + Recovery ≥70 | PASS |