Tachycardia [Explained]

In today’s micro lecture, Australian Paramedical College Hon. Snr. Lecturer Sam Willis discusses ECG and the three different types of tachycardia which refers to a fast heart. We will discuss: sinus tachycardia, supraventricular tachycardia, and ventricular tachycardia.

In today’s micro lecture, we’re going to talk about the three different types of tachycardia. Now, as you well know, tachycardia means fast heart. Tachy meaning fast, cardia is relating to the cardiac system, the heart. Now, tachycardia start at 101 beats per minute. So anything over 100 beats per minute is defined as a tachycardia.

Now, the three different types we’re going to talk about are sinus tachycardia, supraventricular tachycardia, and ventricular tachycardia. Now, this image here to the untrained eye is called a sinus tachycardia. The reason it’s a sinus tachycardia is because, number one, its fast. If you were to do one of your calculations on this, you’ll see it’s above 100 beats per minute. The reason we call it sinus is because, there’s a P wave before every QRS.

P, P, P, P, P. So there are the P waves. The reason we call that sinus is, because the heart beat originates from the sinoatrial node, sino/sinus tachycardia. So whenever there’s a P wave, that means it’s originating from the sinoatrial node. With the Sinus Tachycardia, you really are wanting to ask your patient lots of questions.

There are so many different things that can cause this, including high temperature, fever. Maybe some kind of acute drug overdose can cause it. Stress and anxiety. Sometimes you guys just even being there in new uniforms can cause this. So your history taking will really focus around the cause. This is the best type of tachycardia to have.

The next type is called supraventricular tachycardia. This is a problem with the conduction system of the heart. Now, immediately you see that these things here. You don’t know whether these are the P wave or the T waves, and you don’t even bother trying to interpret it.

What you do do is notice the rate. Straight away, you noticed the rate is approximately 150 beats per minute. That’s pretty fast for a supraventricular tachycardia. It needs oppressing straight away. We would always follow the acute dysrhythmia guideline of making sure that this patient is stable, that the rate is regular, that the patient doesn’t have certain signs and symptoms.

Then we would do vagal maneuvers. In other words, you would try and activate the 10th cranial nerve, which is known as the vagal nerve. The vagal nerves need to be stimulated, and it would slow this down.

The final one we need to look at is ventricular Tachycardia. Now this is a cardiac arrest rhythm. You would the only generally see patients in cardiac arrest. Although, there have been reported cases of patients having this who have been conscious, but they don’t stay conscious for long.

As you can see here, there’s no P waves, there’s no QRSs here. It’s basically just a mess. Which actually, it actually is just QRSs, but not in the way that you might think. It’s not contracting. The ventricles are not contracting in a way, that allows blood to flow to the heart. So there is not your typical QRS complex.

Instead you’ve got these broad bizarre QRSs. And at least on this rhythm here, you can see that it’s regular. It’s a pattern, it’s very fast. It’s a pattern, but unfortunately it’s not sustainable with life.

That’s the three tachycardias. I hope you’ve enjoyed this lecture. Please remember to go and do your reading. My name’s Sam Willis, and I look forward to speaking to you again shortly, guys.

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