Interactive physiology

ECG Atlas

Every ECG change, drawn live on ECG paper with its criteria, the leads where it shows, and what to do next.

25 mm/s · 10 mm/mV small sq 40 ms · 0.1 mV large sq 200 ms rate 60–100 P <120 ms, <2.5 mm in II PR 120–200 QRS <120 (110–119 incomplete) QTc ≤450 men, ≤460 women QTc >500 high risk · short <340–360 axis −30° to +90°

Rate and rhythm

Sinus rhythm

Rate75/min
PR160ms
QRS90ms
QT390ms
QTc415ms, Fridericia
Axis+39°normal
Lead II Sinus rhythm

Criteria
Leads
Causes
Next

Distribution

Twelve leads

Where a change shows tells you where it is. Red leads carry the change, blue leads the reciprocal or mirror image. Picking a pattern here also loads it into the monitor; tap a lead to show it there.

Sinus rhythm

changereciprocal or mirror

Standard layout: I, II, III / aVR, aVL, aVF / V1–V3 / V4–V6, each 2.5 s, with a 10 s lead II rhythm strip. On a narrow screen the leads fold into two columns. Limb leads III, aVR, aVL and aVF are calculated from I and II, as the machine does.

Vectors

Why twelve views

The heart's electrical activity at any instant is one arrow. Each lead reports only the shadow of that arrow on its own axis, so the same beat is upright where the arrow points toward a lead and inverted where it points away.

Arrow tip traces the P loop (blue, drawn ×3), the QRS loop and the T loop (orange). The flat ring is the frontal plane of the limb leads; the tilted ring is the horizontal plane of V1–V6. Drag to turn it.

PQRSTselected lead

Bedside

Measure it

Six calculations that come up on every ward round. Each gives a verdict and shows its working.

ms

    Interpretation

    Read it systematically

    Enter what you see, in the usual order. The report follows rate, rhythm, axis, intervals, morphology and ST–T, then sums up and offers the matching pattern in the monitor.

    Examples are illustrative values, not real patients.

    /min
    ms
    ms
    ms
    ST and T findings (tick any)

      Reference

      Index of changes

      Every pattern on this page. Filter by word or category; tap a row to load it into the monitor.

      ChangeKey criteriaLeadsCausesNext step