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This content is taken from the St George's, University of London & Kingston and St George's Faculty of Health, Social Care and Education's online course, ECG Assessment: an Introduction for Healthcare Providers. Join the course to learn more.

Skip to 0 minutes and 9 seconds Ventricular arrhythmias– an introduction. Ventricular arrhythmias is an umbrella term used to describe abnormal rhythms originating from the ventricles themselves. On the ECG, they’re characterised by abnormally wide QRS complexes, fast heart rates, and typically, the absence of visible P waves. Examples include premature ventricular contractions, ventricular tachycardia, and ventricular fibrillation.

Skip to 0 minutes and 43 seconds Ventricular tachycardia arises when an area within the ventricles generates an impulse in a regular fashion and at a very fast rate. Because the impulses are derived from outside of the normal conduction pathway, they take longer to depolarise the ventricles, and therefore the QRS complexes are wider. The abnormal, rapid depolarizations can significantly impair the heart’s ability to pump blood. So emergency treatment may be required, depending on the presentation.

Skip to 1 minute and 20 seconds On the ECG, you will see wide, bizarre-looking QRS complexes. The rate is fast and regular, and typically, no P waves are seen.

Skip to 1 minute and 36 seconds Ventricular fibrillation arises when multiple areas within the ventricular muscle generate electrical impulses in a very rapid and random fashion. The chaotic activity leads to uncoordinated ventricular contraction, and a failure in the heart’s ability to pump blood. Someone with this arrhythmia will therefore be unconscious with no pulse, and will require emergency advanced life support.

Skip to 2 minutes and 6 seconds The chaotic ventricular activity is represented on the ECG as irregular waveforms with no discernible pattern.

Ventricular arrhythmias: an introduction

Abnormal heart rhythms occur when the electrical impulse does not originate at the sinus node and follow the normal path through the atria and ventricles.

In this presentation, we look at the other main type of abnormal heart rhythms (or arrhythmias) which can occur: ventricular arrhythmias. In particular, we will explore the origin and ECG features of ventricular tachycardia and ventricular fibrillation.

As this is a powerpoint presentation, we’ve also created an illustrated transcript for you to download in the download section.

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ECG Assessment: an Introduction for Healthcare Providers

St George's, University of London