Electrode → ECG Simulator

See how the 12-lead ECG is built from the electrodes — and what happens when something goes wrong.

Break an electrode or cross a cable → watch exactly which leads change and which one is spared.
Add real artifacts — mains hum, baseline wander, muscle noise, loose-contact dropout — then use the filters to clean them up.
Load a real ECG (CSV) or test yourself in quiz mode.

For cardiology trainees, students and clinical staff. Built by Dr Dinesh Raja Palanisamy, grounded in Mondal & Raja et al., World J Cardiol 2026.

Educational only — synthetic ECG, not for clinical diagnosis.

Electrode → ECG Simulator

Vectorcardiographic 12-lead teaching instrument

CardioRender running · 25 mm/s · 10 mm/mV

Quiz mode

Test yourself: the simulator hides a fault — read the strip and name it.

Data source

Signal

A clean normal sinus ECG is the substrate — everything below shows how electrode faults, cable reversals and noise alter it, and how filters recover it.

Show VCG loops (frontal + horizontal)

Rhythm

Heart rate 72 bpm

Run

Paper speed

mm/s — 25 standard · 50 spreads complexes · 12.5 compresses

Gain

mm/mV — 10 standard. A 1 mV cal pulse sits at each strip's left edge.

Limb-lead reversal

Cable error

All four limb cables correct.

Placement

Mason-Likar (torso limb leads)

Rightward axis shift, reduced I/aVL; chest leads stable.

Artifacts

On electrode

Powerline 20%

Frequency Harmonics

Mains hum + harmonics. The notch rejects the fundamental and its harmonics — turn it on and the hum clears.

Baseline wander 37%

Drift rate 0.28 Hz

Respiration + slow drift. Low-freq → removable by high-pass; big excursions push the trace off-scale.

Noise (EMG) 21 µV

Broadband muscle noise in µV RMS. A 1 mV lead tolerates a few tens of µV; above ~120 µV the waveform is buried.

Loose electrode 50%

Events 5

Includes

Step transients / dropout / rail at the electrode — appears coherently in every lead that uses it (spared lead stays clean).

Filters

High-pass 0.05

↑ raise to kill baseline drift; above ~0.5 Hz it starts distorting the ST segment.

Notch (mains) — removes powerline

Low-pass 150

↓ lower to smooth EMG / muscle noise; too low blurs the QRS.

How it affects the leads

Electrode → leads

RA I · II · aVR · aVL · aVF · all V*

LA I · III · aVR · aVL · aVF · all V*

LL II · III · aVR · aVL · aVF · all V*

V1–V6 its own lead only

*chest leads share the Wilson Central Terminal (RA+LA+LL)/3, so a faulty limb electrode contaminates them too. Affected leads flag amber on the strip.

Lead-distribution diagram (Fig 9)

Recognition logic (Fig 10)

Suspected artifact

1 Rate physiologically plausible?> 300 bpm → artifact

2 Ancillary (SpO₂ / arterial line) normal?normal → artifact

3 Real P/QRS/T marching through?yes → artifact (true complexes visible)

4 Fixed coupling just after each QRS?yes → mechanical (pulse-tap) artifact

5 Lead distribution:

All leads → equipment / environmental (mains, cautery)

One limb lead spared → that limb electrode is the culprit

Single chest lead → local electrode fault

Golden rule: never treat the ECG before you check the patient.

Frontal QRS axis: —
Einthoven II−(I+III): —

About · disclaimer · citations

Educational simulator — not for clinical use. The tracings are synthetic and, for pathologies, approximate. Do not use for diagnosis, treatment, or any patient-care decision.

What is exact: lead formation (Einthoven/Goldberger), electrode reversals, artifact-to-lead distribution via the Wilson Central Terminal, and filter behaviour all follow the physics directly — that is the whole point of this module.

The underlying ECG is a synthetic normal-sinus waveform (a single cardiac dipole projected through the Dower transform) — realistic but idealised. This is a teaching module about electrodes, cable reversals, artifacts and filters, not a pathology library.

Citations
Mondal S, Raja DP, Muslim NA, Prabhu MA. Electrocardiographic artifacts in clinical practice: a logical approach to recognition and prevention. World J Cardiol 2026;18(3):116299.
Dower GE, et al. Deriving the 12-lead electrocardiogram from four (EASI) electrodes / the Dower transformation. J Electrocardiol 1988.
Kors JA, et al. Reconstruction of the Frank vectorcardiogram from standard leads. Eur Heart J 1990.

Zoom 100%