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Ventricular paced rhythm on an ECG strip

A pacing spike before every wide QRS, with no P waves.

What to look for

Every QRS has a pacing spike in front of it and is wide (a right ventricular lead gives a left bundle branch block shape), with its T wave pointing the opposite way. You won't find P waves. Underneath, the atria are fibrillating, which is a common reason for this mode.

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
84/min, the pacing rate8 QRS complexes in 6 seconds × 10 = 80/min
Rhythm
Regular
P waves
None: fine fibrillatory baseline
P to QRS
No P waves (atrial fibrillation underneath)
PR
None to measure
QRS
0.18 s, wide
Pacing
VVI at 84/minEvery spike captures
Example 2 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
77/min, the pacing rate8 QRS complexes in 6 seconds × 10 = 80/min
Rhythm
Regular
P waves
None: fine fibrillatory baseline
P to QRS
No P waves (atrial fibrillation underneath)
PR
None to measure
QRS
0.16 s, wide
Pacing
VVI at 77/minEvery spike captures
Example 3 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
79/min, the pacing rate8 QRS complexes in 6 seconds × 10 = 80/min
Rhythm
Regular
P waves
None: fine fibrillatory baseline
P to QRS
No P waves (atrial fibrillation underneath)
PR
None to measure
QRS
0.17 s, wide
Pacing
VVI at 79/minEvery spike captures

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 Paced group