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ECG trainer

Ten rhythms worth recognising on sight, drawn on standard paper so you can measure them the way you will have to. Every trace is generated from a description of the rhythm, not copied from a recording.

72/min, regular

Normal sinus rhythm

Lead II

Standard paper: one small square is 0.04 s across and 0.1 mV high, one large square 0.2 s and 0.5 mV. The step at the left is the 1 mV calibration pulse.

What to look for

A P wave before every QRS, and a QRS after every P
PR interval constant at about 0.16 s, inside the normal 0.12 to 0.20
Narrow QRS, under 0.12 s, so conduction is through the normal system
Regular R-to-R intervals

What it is

This is the reference against which every other strip is read. Work through it the same way every time: rate, rhythm, P waves, PR interval, QRS width, ST segment. Naming the rhythm before finishing that list is where most errors happen.

Told apart from

Sinus tachycardia and sinus bradycardia are this rhythm at a different rate. The relationships between P, PR and QRS are unchanged, which is what makes them sinus.

First step

None. This is the target.

These traces are synthesised so that they are unambiguously what the caption says. A real recording carries noise, artefact and lead placement that this cannot teach. How this content is written.