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Idioventricular rhythm on an ECG strip

Regular wide complexes at 20-40/min, with no P waves.

What to look for

A regular rhythm of wide, bizarre complexes at 20-40/min, with no P waves. Nothing faster is reaching the ventricles, so their own pacemaker has taken over. On this strip, the sinus node has stopped.

Examples

Each strip is 6 seconds of lead II, drawn to scale (25 mm a second, 10 mm a millivolt), so you can count boxes the way you would on paper. Each one is a different example, measured below it.

Example 1 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
24/min2 QRS complexes in 6 seconds × 10 = 20/min
Rhythm
Regular
P waves
None
P to QRS
No P waves
PR
None to measure
QRS
0.14 s, wide
Example 2 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
36/min3 QRS complexes in 6 seconds × 10 = 30/min
Rhythm
Regular
P waves
None
P to QRS
No P waves
PR
None to measure
QRS
0.18 s, wide
Example 3 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
20/min2 QRS complexes in 6 seconds × 10 = 20/min
Rhythm
Regular
P waves
None
P to QRS
No P waves
PR
None to measure
QRS
0.16 s, wide

Don't confuse it with

Want a new strip every time? The ECG Drill in the app draws a fresh, measured example on every try and steers you toward the rhythms you miss. It's part of the Paramedic level, and you can try 5 strips a day free.

Try the ECG Drill

Where the criteria come from

Others in the Ventricular group