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ECG Rhythm Lab
A live simulated patient monitor. Watch the ECG, pulse oximetry and capnography sweep together in real time, pick a rhythm from the library and read how to call it, or switch on quiz mode and identify rhythms until it is reflex. Seven core rhythms carry 34 tracings between them, so hitting Load another pulls a different rate, a coarser or finer fibrillation, or a new conduction ratio. In the field the same rhythm never looks quite the same twice, and that is the point. Rhythm interpretation is a core skill in PCP and ACP programs. EMR courses do not train monitor interpretation, but these rhythms are still worth knowing on sight: what a defibrillator will and will not shock, and the normal baselines that make the rest stand out.
Call it with confidence on a 3-lead monitor: this is a rate, regularity, and conduction question.
How to read it
- Rate: count the R waves. 60 to 100 is normal.
- Rhythm: R to R spacing is even and regular.
- P waves: one upright P before every QRS in lead II.
- Intervals: PR 120 to 200 ms, QRS under 120 ms.
Cut it up: tap a factor
The sequence method: land on an R wave at a heavy line, then name the next heavy lines 300, 150, 100, 75, 60, 50. Where the next R wave falls is the rate. This rhythm runs 60 bpm, a normal rate. Normal is 60 to 100.
Regular rate and rhythm at 60 to 100 bpm. Upright P wave in lead II. PR interval 120 to 200 ms. QRS under 120 ms. Normal axis.
Sick or not sick: how it is managed
Read the patient: Normal sinus is the baseline, so the question is whether the patient's symptoms fit the rhythm or point somewhere else.
Stable / not sick
No rhythm treatment is needed. Confirm perfusion, treat what the patient actually complains of, and keep monitoring.
Unstable / sick
A sick patient with a normal rhythm is not sick from the electrical activity, so look off the monitor for shock, sepsis, or another driver.
Educational only. Follow your current protocols and medical direction.
Simulated waveforms for training only. Not a medical device and not for clinical use.
More rhythms · Sister site
These are the core 7 rhythms. The full library runs 25.
Nothing on this page is locked. What Delta offers free is all here, in full, and every rhythm above carries several variant tracings so the same name never looks identical twice. The complete monitor suite is built at Semparo Institute, our sister training company:
- 124 ECG tracings across 25 rhythms: arrhythmias, blocks, ischemia and electrolyte patterns
- 12-lead and 15-lead interpretation
- SpO2 and capnography waveform teaching
- Levelled rhythm tests and a medical question bank
Also over there: the medical foundation question bank and the medical terminology glossary . The glossary is free to read and downloads as a printable PDF.
Semparo Institute (semparo.ca) is a separate company under the same owner. Delta courses and certificates are unaffected either way.
Vendor neutral on purpose: we teach ECGs and patient assessment, not devices. What you learn here reads the same on whatever monitor or AED your service runs.
A free study aid from Delta Emergency Support Training. This is a simulator, not a diagnostic tool, and not medical direction. Simulated tracings are idealised; real patients are noisier. Always follow your own protocols and medical oversight.
Want the full suite?
Everything on this page is free and open. Want to go deeper? 124 ECG tracings across 25 rhythms, plus 12-leads, capnography and the levelled tests, all live on our sister site, Semparo Institute.
Explore Semparo Institute trainingsemparo.ca, our sister site