Cardiac Arrhythmia: Dysrhythmias and CSD

by Carlo Raj, MD

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    00:00 Now, with dysrhythmia, a conduction system.

    00:03 What are the two ends of the spectrum? Either too slow or too fast. With the bradyarrhythmia, our topic will bring us to heart blocks. With this, most common type of blocks that we will take a look at, AV nodal block. First degree, second degree. With second degree, we will then divide that into Mobitz. But we will only take a look at type 1 and type 2 and then we will walk into our third degree AV block. On the other end of the spectrum. Too quick. I will quickly walk you through, now passive reinforcement so that you feel comfortable with arrhythmia. As soon as your atria, well what exactly are we going to be looking at or interpreting so that you can figure out that your patient has an arrhythmia. How about an EKG? Will that come in handy? Short one. So if you have an atrial type of arrhythmia, what kind of wave are you automatically looking at, please? The P wave right. Now let us say that you add afib okay. That afib where you are lying to or anything, but afib in the sense of afibrillation. Afibrillation is one in which that wave has disappeared.

    01:13 Is that clear? Or has it become wavy. Difficult to identify, obscure. Can we agree upon that? I hope so. So if you have atrial fibrillation, what wave is this? The P wave has now become very obscure to identify. Let us continue. Atrial flutter. You pay attention to two 'T's in the middle of flutter okay and the reason for that is because you want to think of a sawtooth type of appearance of your P wave. Why P wave? Atria. Multifocal atrial tachycardia, MAT. This once again will be an issue with your atria. So what does the P wave look? They look abnormal. They look bizaare. The P waves do. It doesn't touch the QRS complex, is that clear? And then we have WPW, Wolf-Parkinson-White syndrome. What is this? It is an excessory pathway. "What does that even mean, Dr. Raj?" It means that remember the proper conduction of an impulse is going to be from the SA node, you have to go to a delay. Why did you need that delay at the AV node? You need that delay so that you have just enough time. As you squeeze the blood from the atria to the ventricle, right. You need just enough time in a delay in which you have enough time to properly fill up the ventricle. Correct? Who is going to provide that delay? I believe it is called the atrioventricular node. The AV node okay. That is perfectly normal physiologic conduction. What if you accidentally, inheritently ended up having an accessory pathway anywhere along the intraatria or shall I say between the atria and the ventricle? So if you had some type of accessory pathway on the septum or the wall between the atria and the ventricle, well this will not provide a delay. This is that accessory pathway that you are referring to. And so, therefore, we will talk about what is called as a AV nodal reentry type of arrhythmia. Not good. And the particular characteristics that are very important for you to clinch WPW as a diagnosis. Okay. So that is the atria.

    03:17 But in general, what is going on? Tachy, too fast. What are normal beats per minute? 60 to 100 okay. 60to 100 is normal beats per minute. So if it is tachy, greater than 100, by definition automatically tachy. Less than 60, automatically brady. Is that clear? So this is algorithm 100. Ventricular, what are you going to effect? What wave are you going to affect here with ventricular issues? Hopefully, you are telling me QRS correct. The QRS complex represents the activity of the ventricle. So, therefore, let us say that you have twisting around your point.

    03:59 How do you say that in French? Torsades de pointes. You are twisting around a point. Who is? The QRS complex. Wow! That is dangerous, isn't it? What predisposed of this? Most likely, maybe some kind of long QT issue. So when the QT becomes more and more prolonged, why? Maybe drugs such as antibiotics, such as antipsychotics, such as quinidine, a bunch of drugs may result in a secondary long QT. Inheritently you can have genetic diseases. You have heard of romano-ward right, in which there is no deafness. You have heard of things such as Lange-Nielsen. So these are the inheritent type of long QT syndromes.

    04:51 What does that even mean? The more that you prolong your QT, the QRS complex doesn't know how to behave so, therefore, it starts twisting around the point, is that clear? So understand the most common predisposing factors. And once you do, things become a heck of a lot easier. Ventricular fibrillation, you should feel very comfortable with the term fib, fibrillation. What does that mean? A disappearance or obscure type of wave. Can't tell you how to identify. But in this case, the ventricular. So it is difficult to identify the QRS complex. Oh! My goodness. Picture this. The QRS complex is difficult to identify. It is wavy. It is almost like a flat line. What does flat line mean to you? You are sleeping forever. You are dead. So ventricular fibrillation. You are worried about death, aren't you? You'd never want to get to that point. In fact, whenever you have any type of arrhythmia and if it is originating in atria known as supraventricular arrhythmias right. Whenever you have supraventricular tachycardias, what is your number one mission? What is your objective? You do everything in your power to prevent that arrhythmia from going into the ventricle because if it does oh! My goodness take a look at this ventricular fibrillation. You are going crazy, who is? The ventricles are. What does that mean? You can’t properly fill up your ventricles with blood. How in the world are you supposed to have cardiac output? You don't. Is your patient going to die? Yes. Are you putting things together? I hope so. Ventricular tachy. Well, all these mean that the QRS complex, this band between them is getting very short. The R wave to R wave.

    06:30 Think about R wave, major pulse deflection. The R wave to R wave is going to shorten.

    06:36 You might have heard of mnemonics or paramedics or what not and they talk about 300, 150, 100 and 75, 60, 50. It's like a phone number and what does that mean is that the fact the lines as I should show you an EKG. The lines when they are closer together, is that tachy or is that brady, please? Tachy okay. I will show you that. If you missed it, that is okay. Don't worry. I am just introducing. What I like to do as you know is to bring information from before and then introduce information to be had. But ultimately, reinforcement.

    07:09 Let us begin. So now with vascular disease, the only other category here with arrhythmia where let us say that she had a myocardial infarction okay. Once again let us say in left anterior descending, you will find an ST elevation, in which leads would you find ST elevation if your left anterior was undergoing infarction? A major embolic obstruction. Got it? Good. What is it? V1 through V4. Are you picturing in this? Good. So left anterior descending, there is a myocardial infarction, you'll ST elevation in V1 through V4. So that's your intraventricular area and may be anteroapical and that is some point well, this used to be called the widow maker, why? Because if the patient had an LAD type of MI, chances are they are not coming back and it ends up where the spouse is lost, right. That is unfortunate. My point is this, though. If there is myocardial infarction and the wall is not working properly, could it result in arrhythmias? Sure it can. Venous insufficiency, peripheral vascular disease, peripheral arterial disease. Any one of these could result in decreased perfusion to the heart and some may result in arrhythmia. Aortic dissection. This itself let us that you have an issue such as Marfan disease. What is that called when you have little bit of tear and there is accumulation of fluid from the intima into the media? Cystic medial necrosis may result in eventually aortic dissection, with vascular diseases. Once again if there isn’t proper blood supply to the heart and you have origination of your arrhythmia. Interesting, isn't it? So you can have these inheritent causes that we just walk through or vascular diseases, but you have to take a look at the body in totality for you to truly make sense of this.

    About the Lecture

    The lecture Cardiac Arrhythmia: Dysrhythmias and CSD by Carlo Raj, MD is from the course Arrhythmias.

    Author of lecture Cardiac Arrhythmia: Dysrhythmias and CSD

     Carlo Raj, MD

    Carlo Raj, MD

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