Chaotic, VF-looking waves over part of the strip, but the patient's own QRS complexes keep marching through them on time: it's movement or tremor, not a rhythm.
Before you charge the pads, look at the patient and at the strip. VF has no QRS complexes. Here the patient's own narrow QRS complexes keep coming through the mess, right on schedule: walk calipers across from the clean part and they land on each one. Movement, shivering, seizure activity, CPR, a loose lead or a bumpy road can all do this. The rate can look impossibly fast, it starts and stops abruptly with no R-on-T beat to set it off, and the pulse oximeter and the patient say otherwise. A talking patient is not in VF.
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.
Chaotic waves of varying size, with no P waves, QRS complexes or T waves.
A wide-complex tachycardia whose complexes change shape from beat to beat.
Irregularly irregular, with no P waves: only a fibrillating baseline.
Polymorphic VT that twists around the baseline in spindles, following a long QT.
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
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