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Sinus rhythm with unifocal PVCs on an ECG strip

Sinus rhythm with early wide bizarre beats, all one shape, with no P wave and a full compensatory pause.

What to look for

Early, wide, bizarre complexes with no P wave and a T wave opposite the QRS, all the same shape (unifocal). The sinus P that's due during the PVC doesn't conduct, so the beats on either side of a PVC land exactly two sinus cycles apart. That's a full compensatory pause.

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 underlyingThe whole strip averages 84/min · 8 QRS complexes in 6 seconds × 10 = 80/min
Rhythm
Regular underneath, with early beats breaking it
P waves
Upright in II, uniform
P to QRS
1:1 for the sinus beats; the PVCs have no P wave
PR
0.19 s
QRS
0.09 s, narrow
PVCs
2 on this strip
Example 2 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
69/min underlyingThe whole strip averages 75/min · 7 QRS complexes in 6 seconds × 10 = 70/min
Rhythm
Regular underneath, with early beats breaking it
P waves
Upright in II, uniform
P to QRS
1:1 for the sinus beats; the PVCs have no P wave
PR
0.20 s
QRS
0.09 s, narrow
PVCs
2 on this strip
Example 3 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
78/min underlyingThe whole strip averages 83/min · 7 QRS complexes in 6 seconds × 10 = 70/min
Rhythm
Regular underneath, with early beats breaking it
P waves
Upright in II, uniform
P to QRS
1:1 for the sinus beats; the PVCs have no P wave
PR
0.20 s
QRS
0.11 s, narrow
PVCs
2 on this strip

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