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Asystole on an ECG strip

No QRS complexes at all: a flat line, sometimes with P waves alone.

What to look for

No ventricular electrical activity, just a flat line with no QRS complexes. In P-wave asystole (ventricular standstill), the atria are still beating, so P waves show up with nothing after them. Fine VF can look a lot like asystole. If you can see waves of any regular rhythm, it isn't asystole.

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
No QRS complexes
Rhythm
No rhythm: no QRS complexes
P waves
Upright in II, uniform; nothing follows them
P to QRS
P waves with no QRS after any of them
PR
None to measure
QRS
None
Example 2 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
No QRS complexes
Rhythm
No rhythm: no QRS complexes
P waves
None
P to QRS
No P waves and no QRS complexes
PR
None to measure
QRS
None
Example 3 · lead II · 6 seconds
II25 mm/s · 10 mm/mV
Rate
No QRS complexes
Rhythm
No rhythm: no QRS complexes
P waves
None
P to QRS
No P waves and no QRS complexes
PR
None to measure
QRS
None

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