Not medical advice A teaching model — not a diagnosis, treatment plan, or measurement of any patient. It models long-term blood-pressure, sodium and fluid regulation (the chronic substrate of cardiovascular risk) — not an acute heart attack (myocardial infarction). Every reading is an interpretation of the math. Source: Karaaslan et al. (2005), Annals of Biomedical Engineering.

Heart Lab The long-term cardio-renal loop, and the set-points it settles into

A reduced long-term cardiovascular/renal model in the spirit of Karaaslan et al. (2005). Watch the coupled loop — renal sympathetic drive (RSNA) → arterial pressure (MAP) → sodium & fluid volume → the renin–angiotensin–aldosterone (RAAS) hormones — find its steady state. The lab's point: a disease state is the loop regulating to the wrong set-point, not the loop breaking.

Math basis: Karaaslan, Denizhan, Kayserilioglu & Gulcur (2005), Ann. Biomed. Eng. Vanilla JS + Canvas, zero dependencies Reduced model — directional, not bit-exact Not medical advice
The coupled loop — RSNA → MAP → sodium/volume → RAAS
Canvas is unavailable in this browser. Showing the latest computed steady-state values instead of the animated loop.
normal MAP 100 mmHg · settling…
What's happening
The healthy loop is converging toward its normal steady state.
Why it might matter interpretation
At steady state, sodium intake equals sodium output and pressure self-sets via pressure natriuresis. A disease preset shifts where that balance lands.
Under the hood
RSNA 1.00 · MAP 100.0 mmHg · M_sod 2160 mEq · V_b 5.00 L · renin 1.00
Physiological state
A model parameter preset, not a patient. Adjust the controls below to explore between them.
Clinical controls
Drag to explore the loop between disease states. Each control is a clinical knob — no equations. Extremes are clamped to a safe physiological range and labeled.
Run
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FPS
0
Model min
100
MAP
The viewer integrates the model on a fixed timestep and animates the live state. On a backgrounded tab it pauses; on a slow device it caps work per frame rather than freezing.
Disease-attractor explorer

Every cell is a precomputed steady state: dietary sodium load (left→right) against sympathetic tone (bottom→top), coloured by the set-point the loop settles into. Drag the control to walk the sodium axis at the current tone and watch the set-point slide from a compensated value toward a decompensated one. Each cell is a single stable set-point (a point attractor) the loop slides to smoothly — in this reduced model there is no hidden threshold to cross and no bistability, so the slide is gradual and fully reversible.

Healthy set-point
Hypertension attractor
CHF / decompensated
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What this is, what this is not

Heart Lab is a teaching toy built on a reduced long-term cardio-renal model. It is not a clinical tool, a diagnostic instrument, or a treatment plan.

1. What this is. A deterministic generative model that captures the documented long-term causal chain of Karaaslan et al. (2005) and converges to the paper's normal steady-state values. It is a directionally-faithful reduction, not a bit-exact reproduction of the full block model.

2. What the labels are. "Hypertensive", "hypertensive crisis", "decompensated" are clinical vocabulary applied to the model's regime. They are interpretations of the math, not measurements of any patient. Out-of-range dynamics are clamped to physiological bounds and flagged as a labeled state rather than shown as an error.

3. What this is not. Not a diagnosis, not a treatment plan, not validated against any clinical outcome. Disease-state fidelity and clamp-range defensibility are under scientific-advisor review.

Source: Karaaslan, F., Denizhan, Y., Kayserilioglu, A. & Gulcur, H.O. (2005). Long-term mathematical model involving renal sympathetic nerve activity, arterial pressure, and sodium excretion. Annals of Biomedical Engineering 33(11), 1607–1630.