ECG rhythm quiz: what is on the monitor?
Each clip shows a running monitor with no rhythm name on the screen. Read it, say your answer out loud, and the video gives the answer after a five-second countdown.
How to use the quiz
Look at the whole monitor, not only the ECG. Several of these are decided by the arterial pressure or the pleth, the same way they are at the bedside: an organised rhythm with no pressure is a cardiac arrest, however tidy the complexes look. The hint under each video tells you where to look. The answer stays folded away until you open it.
Teaching a group? Put a clip on the projector and pause it before the countdown runs out. Ask for the one feature that gave it away before anyone is allowed to name the rhythm. For the AV blocks, this drill guide goes through what to ask.
Rhythm 1
Is the rhythm regular? And where are the P waves?
Show the answer
Atrial fibrillation. Irregularly irregular, no P waves, only an uneven baseline. The pulse waves change height from beat to beat.
Rhythm 2
Look at the rate, and at the baseline between the beats.
Show the answer
Atrial flutter, 2:1. Sawtooth flutter waves at about 300 a minute. Every second one gets through, so the rate sits at 150.
Rhythm 3
Narrow or wide? And can you find any P waves?
Show the answer
Supraventricular tachycardia. Narrow, regular and very fast, around 180, with no P waves you can pick out.
Rhythm 4
Look at the width of the QRS complexes.
Show the answer
Ventricular tachycardia. Wide, fast and regular. This patient still has a pressure on the monitor, so it is VT with a pulse.
Rhythm 5
Look at the numbers as well as the trace.
Show the answer
Ventricular fibrillation. Chaotic waves and no QRS complexes. The monitor cannot count a rate and there is no pressure. Start CPR and defibrillate.
Rhythm 6
What would you check before calling it?
Show the answer
Asystole. No electrical activity at all. Before you call it, check the leads, the gain and a second lead.
Rhythm 7
Look at the whole monitor, not just the ECG.
Show the answer
PEA. Organised beats and a heart rate, but no pressure and no pleth. Pulseless electrical activity: treat it as cardiac arrest.
Rhythm 8
Measure from the start of the P wave to the QRS.
Show the answer
First-degree AV block. Every P wave gets through, just late. The PR interval is longer than 0.2 seconds.
Rhythm 9
Watch the gap between the P wave and the QRS complex.
Show the answer
Mobitz type I (Wenckebach). The PR interval gets longer with every beat, until a QRS complex drops out.
Rhythm 10
Do the P waves and the QRS complexes belong together?
Show the answer
Third-degree AV block. The P waves and the QRS complexes keep their own rates. Nothing gets through, and a slow escape rhythm takes over.
Rhythm 11
Slow and narrow. Is there a P wave before each QRS?
Show the answer
Junctional escape rhythm. No P wave in front of the QRS, only a small inverted one just after it. The AV junction has taken over at about 45.
Rhythm 12
Look at the width and shape of the QRS.
Show the answer
Bundle branch block. Sinus rhythm with a wide, notched QRS and the T wave pointing the other way. Left or right needs leads V1 and V6.
Rhythm 13
Look at the segment between the QRS and the T wave.
Show the answer
ST elevation. The ST segment is raised and runs up into the T wave. Think STEMI and get a 12-lead ECG.
Rhythm 14
Look closely at the T waves.
Show the answer
Hyperkalaemia. Tall, narrow, peaked T waves and a slow rate. Check the potassium.
Rhythm 15
What follows each pacing spike?
Show the answer
Pacing without capture. The pacemaker fires, but no QRS follows the spikes, and there is no pressure. The pacing is not capturing.
Each video asks the question, gives a five-second countdown, then the answer. Plays from YouTube when you click. Nothing loads from YouTube before that.
Practise the same rhythms yourself
Every clip was recorded from the Patient Simulator, a free browser app where a phone controls a monitor shown on a tablet. The rhythm name never appears on the monitor, so you can run the same quiz live in a skills lab and switch rhythm while the students watch. The ECG simulator page lists all 22 rhythms it can show. The pair people mix up most often has its own write-up, AFib vs atrial flutter, and so do the arrest rhythms in teaching PEA vs asystole.
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