ECG RHYTHM LAB

Start with a rhythm.

1. Choose a rhythm at the top. The monitor runs immediately unless your device prefers reduced motion.
2. Use − / + or enter a target rate. For conduction blocks, the control identifies when it represents atrial rate.
3. Select SpO₂, blood pressure, respiratory rate or EtCO₂ to edit simulated values.
4. Open Settings (Setup in Dark monitor) for appearance, sweep speed, gain, artifact, sound and morphology controls.
5. Use Strips, directly or in More, for current-trace capture, new examples, saved strips, PNG download and Print / PDF.

Pause, freeze and reset

Pause stops the simulation clock and tones. Freeze holds the display while time continues. Reset restores the selected rhythm’s default rate and morphology, keeping vital signs and display preferences.

Practice

Choose Practice, identify one of four options, then read the identifying feature. All 22 identification-ready rhythms appear before the cycle repeats. Exit restores your previous monitor. Torsades remains a simulator-only teaching pattern.

On a phone

Portrait stacks the ECG, readings and supporting signals. Short landscape prioritizes the ECG and heart rate; All signals expands the other readings. Add to Home Screen in your browser for an app-style view after HTTPS deployment.

Spacing and rate

At 25 mm/s: one small box is 0.04 seconds; one large box is 0.20 seconds. At 50 mm/s: 0.02 and 0.10 seconds. Display millimetres are simulated, not physically calibrated.

For regular rhythms at 25 mm/s, divide 300 by large boxes or 1500 by small boxes between R waves. Double the numerator at 50 mm/s. For a six-second strip, count QRS complexes and multiply by 10 for approximate ventricular rate. ECG rate does not establish a palpable pulse.

Measure PR from P onset to QRS onset; QRS duration from first deflection to its end.