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🔬 Phase 1 · Public Data · Reproducible

The physics
shows up in the data.

A single scalar feature — the fractal-scaling exponent of beat-to-beat intervals — separates severe heart failure from normal sinus rhythm at AUC 0.942 on public PhysioNet data. The multivariate HRV model hits 0.947 ± 0.052, five-fold cross-validated.

Exploratory, not validated. This uses five-fold stratified cross-validation over 82 segments from 31 records. Unless folds are grouped by record, segments from the same subject can fall in both train and test and inflate AUC through subject leakage. A record-grouped re-analysis (leave-one-record-out) is underway — treat these figures as exploratory until it lands.

The Wike Coherence Law predicts this collapse before it's measured: as γeff rises toward the critical threshold γc, cross-scale phase locking fails — and fractal structure with it. This page shows the prediction matching the data.

01
Headline

The numbers.

0.947
HRV-only multivariate AUC
5-fold cross-validated
0.942
DFA α single-feature AUC
Cohen's d = −2.579
82
5-min HRV segments
16 normal · 15 CHF
< 10-4
p-value on top 3 features
Mann–Whitney U test
02
The figure

DFA α — the coherence signature.

A healthy heart sits near α ≈ 1.0 — pink noise, long-range correlations, coherent organization across time scales. In severe CHF, α collapses toward 0.65. The distribution separation is what the framework predicts: decoherence is fractal-exponent collapse.

DFA alpha distribution — NORMAL vs CHF
Figure 1. DFA α distribution overlay. Dashed lines mark group means: Normal α = 1.104, CHF α = 0.649. Single-feature AUC 0.942, p < 0.0001.
03
Per-feature results

Every feature, one row.

Six HRV features computed per 5-minute segment. Cohen's d measures standardized effect size; AUC is the rank-based probability a CHF segment's value exceeds a normal segment's for that feature.

Feature Cohen's d AUC p-value Normal mean CHF mean
DFA α −2.579 0.942 < 0.0001 1.104 0.649
RMSSD (ms) +1.525 0.896 < 0.0001 34.54 191.75
SampEn −0.980 0.756 0.0001 0.877 0.479
SDNN (ms) +0.930 0.708 0.0014 70.63 140.98
pNN50 (%) +0.796 0.699 0.0022 6.49 19.13
mean HR (bpm) +0.223 0.575 0.2489 88.82 92.25
Per-feature AUC bar chart
Figure 2. Per-feature AUC. Gold bars exceed 0.85; the dashed reference line marks the multivariate ceiling.
04
Two-feature view

Where coherence lives. Where it breaks.

Plotting DFA α against RMSSD lays the two cohorts on different manifolds. Normal sits in a narrow fractal band with moderate vagal tone. CHF fans out toward both α-collapse and RMSSD inflation — classic autonomic dysregulation on top of fractal failure.

RMSSD vs DFA alpha scatter
Figure 3. RMSSD vs DFA α, per-segment scatter. Teal circles: Normal. Red triangles: CHF.
05
The prediction

This is what the math said would happen.

C = C0 · exp(−α · γeff)    α = 16.08
Wike Coherence Law

As γeff rises toward the critical threshold γc, coherence decays exponentially. The prediction is that decoherence is not just a loss of amplitude — it is a loss of structure across scales. A coherent biological system shows pink-noise (1/f) fluctuations; a decoherent one loses that scaling and drifts toward uncorrelated noise. DFA α measures exactly that fractal exponent.

CHF is a sustained γeff excursion at the cardiac level. The prediction: α should collapse from ~1.0 toward ~0.5–0.7 as the coherent attractor is lost. The data: Normal α mean = 1.104; CHF α mean = 0.649. That's the prediction, measured.

06
Methods

How the numbers were made.

Data
PhysioNet — Normal Sinus Rhythm Database (nsrdb, 16 records at 128 Hz) vs BIDMC Congestive Heart Failure Database (chfdb, 15 records at 250 Hz, NYHA III–IV). Public. No credentials required. No patient-identifiable information.
Segmentation
First 20 minutes of each recording. Split into three 5-minute non-overlapping windows. 48 normal segments + 34 CHF segments = 82 total.
R-peak detection
WFDB XQRS algorithm with scipy find_peaks fallback. RR intervals filtered to physiological 300–2000 ms (30–200 bpm).
Features
SDNN, RMSSD, pNN50 (time domain) · LF/HF via Welch PSD on 4 Hz cubic-spline-resampled RR (frequency domain) · Sample Entropy m=2, r=0.2·σ · DFA α on box sizes 4–N/4 (nonlinear).
Discrimination
Cohen's d for effect size. Mann–Whitney U for non-parametric AUC and p-values. Multivariate: standardized logistic regression with 5-fold stratified cross-validation.
Reproducibility
Full pipeline is one Python file. Per-record feature cache makes reruns instant. Raw feature CSV + discrimination CSV + summary JSON all downloadable below.
07
08
Phase 2

What we're already building.

Phase 1 answers "does HRV discriminate?" Phase 2 answers the real clinical question: does adding C-reactive protein push the discrimination ceiling above 0.947 in a cancer cohort? That requires paired HRV + inflammation + outcome data, which lives in MIMIC-IV.

01
Pipeline built HRV feature extraction · fusion framework · MIMIC SQL written and tested · per-record caching
Complete
02
Public-data baseline locked NSRDB vs CHFDB — HRV-only AUC 0.947 ± 0.052 — the ceiling the fusion model has to beat
Complete
03
PhysioNet credentialing Account · CITI "Data or Specimens Only Research" training · MIMIC-IV Data Use Agreement signing
In motion
04
MIMIC-IV pull CRP itemid 50889, ±24h window · ICD-10 cancer (C00–D49), CHF (I50), infection (A40–A41) · QUALIFY-deduped cohort join
Awaiting DUA
05
Fusion analysis HRV-only vs CRP-only vs HRV+CRP · AUC lift as primary endpoint · per-subgroup by diagnosis
Awaiting data
06
Publication Preprint on medRxiv · full-repro repo · real CRP results on this page
Planned
09

If you work on this, reach out.

Cardiologists, oncologists, HRV researchers, MIMIC-IV credentialed PIs, journalists, funders. The raw data is above. The pipeline is one file. The hypothesis is falsifiable. The theory predicted the number before the number existed.

Reach out → See the cancer framework

Research and decision-support only · Not medical advice
Does not replace licensed clinical diagnosis or treatment

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