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Hello, everyone. Can you hear me? OK, just pop up in the chat. So my name is Sara. I'm one of the junior doctors in pediatrics at the moment and I've just rotated out from car cardiology about two months ago. Um So I'm doing the session by myself today. So if we could write down the questions you have during the sessions and ask at the end, I can do AQ and a session with you as well. So firstly, thank you for giving up your Monday evening to go over C GS. Um I'm sure it would be helpful come ki time later on. Yes. All right. I will start sharing screen now. OK. So today's session is basically just ecg interpretation. We'll go through the basics in terms of what makes up the electrical pathway um of the heart that causes depolarization, contraction, and the whole cardiac cycle. We'll go through the basic um algorithm through which we interpret an ECG. So that's going to be a rate rhythm and axis first and then you go through your waves, intervals and segments next and then to end it all, we'll do some cases as well. OK. So firstly to go through the electrical pathway, we've got the essay node in your right atrium right at the top in the corner. And that causes depolarization to go across both of your atria to eventually reach your A V node, which is also placed in and around your right atrium. Your A V node access a sort of break and then propagates that signal down your ventricles through your bundle of his, your right and left bundle branches, your left bundle branch then splits into your anterior fascicle which goes at the front and your posterior fascicle which goes down the septum and up your left ventricle, your right bundle branch just goes down septum and goes up your right ventricle and the fibers that go up your ventricle are called the purkinje fibers. Now, in terms of what this relates to in an ECG, we've got the P wave which is represented by your atrial depolarization. So that's going to be your essay node. Anything that goes down your Bachmann's bundle to your left atrium and any of the depolarization within both of those atria there. And then you've got your ventricular depolarization, which is represented by your QRS complex. And then you've got the time for your ventricle to actually pump and then you've got your repolarization of your ventricles represented by your T wave. So, basics of the ECG as with any data interpretation, always check the name, date of birth and your hospital number or address. So three things that identify that patient and check it with your patient in the exam as well. Don't just look at your, your EG and say you've checked it, mention the type of investigation you have at hand. So that's going to be your E CG mention the date and time of investigations of when it was taken and always say you would compare it to a previous ECG. Now this comes in handy when you're doing something like a stemi where you can see changes within 10 minutes of each other. And you can say there is an evolving change in this ecg denoting acute pathology. The next thing you want to do in an ECG is to check the speed, always check it's 25 millimeters per second with one millivolt. So all that means is it's going to be this dimension. So the horizontal axis is the time. So one big box is going to be 0.2 seconds or 200 milliseconds. And one small box is going to be 0.04 seconds or 40 milliseconds. And now looking at the amplitude, which is your vertical axis, one small box is 0.1 millivolts and one big box is very annoyingly 0.5 millivolts as opposed to one millivolt. So the first thing you want to do in an E CG is calculate the rate and that you would be doing using the horizontal axis cos it denotes time the best way to do it is to first know whether your rhythm is regular or irregular. If it looks vaguely regular, just look at the number of big boxes you have between two R waves and 300 divided by the number of big boxes between two R waves gives you the rate. So five large boxes would be 64 would be 75. 3 would be 102 would be 151 box would be 300 BPM or you can do 1500 divided by small boxes. I'm not very good at mathematics. So II never can actually calculate that in my head. So I tend to go either for the 300 method or the easier irregular method where you basically count the number of R waves within the entirety of your rhythm strip at the bottom and times it by six. That way, the only thing you actually need to remember is you're six times stable and you're winning. So the next thing you wanna do after calculating the rate is look at the rhythm, some people tend to do rhythm first and then go on to rate. It really doesn't matter because you tend to sort of describe them together. So the first thing is whether your rhythm is in sinus rhythm, the way you can see that is always look for your P waves. And if each P wave is followed up by a QR S complex without any dropped beats. And if the distance between two hour waves is consistently the same across, if all of those factors meet, you're in sinus rhythm, the best way I tend to do it is to fold up a piece of paper max three airwaves on there and just move it along to the next and the next and the next hour. And if it's consistently falling on those dots more or less, then it is a regular rhythm. So can anyone in the chat sort of put on there? What you think this particular rhythm strip is showing? And someone's bit sinus tachy. Yeah. So it's basically sinus tachycardia. As you correctly pointed out, you can see the P waves very clearly. But what's happened is it's just been buried underneath the QR S complex. The only difference is you tend to say sinus tachy when your heart rate is a little bit on the lower side of tachycardia. So if it's around 100 to 100 and 40 100 and 50 then you would say sinus tachycardia. So here you can see there are only two big boxes between which means it's around 100 and 50 BPM. So at that point, you're sort of entering the regions of saying it's either atrial tachycardia or supraventricular tachycardia. So SVT S but you won't be wrong in pointing out that this is sinus tachycardia and same thing anyone in the chart tell me what this is, someone's were done a S VT S VT. Ok.