Do I need to install anything?

No. It runs in any modern browser, free, with no account required.

For First Responders · Cardiac Action Potential

Cardiac Action Potential for a synapse

Built for first responders planning or training for real incidents. Run fast what-if scenarios for response planning and training — no software to install in the field. Simulate a synapse live below — adjust the inputs and watch it respond, right in your browser.

Cardiac Action PotentialLive

the electrical heartbeat

Controls

Presets

Heart rate (bpm)

Plateau duration

Upstroke amplitude (mV)

Each heartbeat is an electrical wave: a fast sodium upstroke, a long calcium plateau unique to heart cells, then potassium repolarization. That plateau keeps the muscle contracted long enough to pump — and its length sets the refractory period. Educational tool, not medical advice.

▶ Run in Python

Data Inspector

Cycle length857 ms

Action-potential duration343 ms

Peak potential+20 mV

Governing equation

C_{m} \frac{d V}{d t} = - I_{i o n}, \frac{d V}{d t}_{ma x} = \frac{110 mV}{10 ms} = 11 mV/ms

Reading this result: The plateau holds the cell near 0 mV for ~343 ms — the calcium phase unique to heart muscle that keeps it contracted long enough to pump before potassium repolarizes it.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

or unlock everything with Pro →

Also for:Students Researchers Educators Engineers Hobbyists & Makers K-12 Students General version →

More with Cardiac Action Potential

Cardiac Action Potential for a bacterial growth Cardiac Action Potential for a predator-prey cycle Cardiac Action Potential for a neuron firing Cardiac Action Potential for a heartbeat Cardiac Action Potential for a virus spread Cardiac Action Potential for a gene expression Cardiac Action Potential for a protein fold Cardiac Action Potential for a muscle contraction

Frequently asked questions

Is this good for first responders?: Yes — this version of "Cardiac Action Potential for a synapse" is framed for first responders planning or training for real incidents. Run fast what-if scenarios for response planning and training — no software to install in the field.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.