 Hi, welcome to Nursing School Explained and this video in the EKG interpretation series that starts going into ventricular dysrhythmias, specifically premature ventricular complexes or contractions. If you haven't already done so, I highly recommend watching the basic videos on EKG interpretation, where I go into the basic electrophysiology as well as how to determine the EKG paper and the different intervals. So let's look at premature ventricular complexes or contractions arise from an irritable focus in either ventricle and remember that cardiac cells are very specialized cells and any cardiac cell can initiate an impulse and this is exactly what we're dealing with here. This irritable focus can be in either ventricle, so this is an irritable cell that just prematurely, which means earlier than the expected next sinus beat happens and forces a contraction to happen. The QRS complex of a premature ventricular contraction is usually greater than 0.12 seconds, which means that we're now getting into being out of the ordinary of the less than 0.12 seconds and what this means is the PVC depolarizes the ventricles prematurely and abnormally. So this is an early beat that happens early in the cycle, earlier than that we would expect the next beat and it usually looks what they call wide and bizarre because this interval is greater than the 0.12 seconds and then the other thing that's very noticeable here is that the T wave usually is in the opposite direction of the QRS. So let's take a look at this here. There are different types and shapes of PVCs, so they can occur just one by itself or multiple in a row. So a pair usually mean also called couplets means that there's two sequential PVCs, so two PVCs in a row. A run of PVCs or a burst of PVC means three or more sequential PVCs and that's actually also called ventricular tachycardia, which can be a life-threatening dysrhythmia. PVCs can occur in bi-geminy, which means that every other beat is a PVC or a tri-geminy, meaning that every third beat is a PVC or a quadri-geminy, meaning every fourth beat is a PVC. So depending on the prefixes of these words here means by how many beats the PVC skips and then they can also be determined by shapes. They can be unifocal or multifocal, meaning now that we have one irritable focus or multiple irritable foci in the ventricles. So unifocal will be just one and then again multiple irritable foci and that's always worse for the patient because now the ventricle is irritated in more than one locations, which usually means that the patient will have more symptoms and they're higher likely of having runs or bursts of VTAC. Keep in mind down here, this is very important. There is always an underlying rhythm with premature ventricular contractions, just like with premature atrial contractions and that can be any underlying rhythm and we'll look at it going forward here. So looking at the steps of EKG analysis, we're looking at rate, rhythm, P wave and the intervals. So the rate is usually within normal limit but it depends on the underlying rhythm. In this case here, if you really look at it, these beats, these normal beats look pretty normal here and then we have this strange looking bizarre thing in the middle of it, which makes this entire second rhythm strip irregular. So they can be irregular or irregular. The P wave for PVCs is usually absent. So we're only talking about this specific complex now because we can see that we have a P wave here but that would be the underlying rhythm. And then for the PVCs, again this specific one right here, there is no PRI because the PVC, this ectopic beat stems from the ventricle. So it's not going to represent any atrial depolarization because it only occurs in the ventricles. And then here is what we talked about, the QRS being greater than 0.12 seconds and being wide and bizarre. And you can see the shape is very different from anything that we've seen so far. And then also noticeable here, the T wave occurs in the opposite direction of the QRS. So the QRS here goes up from the isoelectric line where the T wave goes in the opposite direction, which is pretty typical for a PVC. Now remember that I just said the PVCs always have an underlying rhythm. So in this case, if we would analyze these regular looking beats here, they would be sinus. And let's just double check to make sure the rate is right. So 1, 2, this would be a beat 3, 4, 5, 6, 7, 8. So high rate of 80. So this would be a sinus rhythm with one unifoco PVC. This is how you would interpret this. And you wouldn't call it a normal sinus rhythm because the PVC is not supposed to be there. So now we can't call it normal anymore. The PVC was not there and we had a normal complex here. Instead, this would be a normal sinus rhythm and we wouldn't even have to worry about talking about a PVC. But whenever there's something an abnormal beat within that sinus rhythm, we don't call it normal anymore. So in this case, sinus rhythm with one unifoco PVC. And then here is an example of a couplet. So now we have two PVCs. They both have the same shape and there's two in a row. So that's a couplet or a pair. And again, this would be an underlying sinus rhythm. So this would be a sinus rhythm with two coupled PVCs, unifoco PVC. Here is another example. So here we have a run. So now we can see 1, 2, 3, 4 abnormal beats. And then here we have 1, 2, 3. And again, you can see that this is wide and bizarre. We can really see that any P wave may be in there somewhere. The Q wave is just very strange. And again, the Q goes up and the T goes down. So it's the opposite direction. Where in a normal beat, the Q, R, S as well as the T wave are usually upright. They go in the same direction. And whenever we have a run or three or more PVCs in a row, it's also called a run of ventricular tachycardia or a run of VTAC or non-sustained VTAC, meaning that there's a short burst of a ventricular tachycardia, but it's not sustained because it goes back to normal. And then here again. So this would be a patient that you want to have a very close eye on because it's highly likely that their ventricles are now so irritated that all of a sudden the few normal beats that the patient has in between here will go away. And this will just turn into ventricular tachycardia. And we'll look at that in a different rhythm strip analysis, but that can be a deadly rhythm. And then here's another example of PVCs in bi-gemini. So you can see a normal beat right here. Actually, it includes this T wave. And then we have this wide and bizarre looking thing right there. And it's every other beat. So it's bi-gemini. So here is our abnormal beat. Here is the abnormal one. Here is abnormal. And here it is abnormal again. And you can see they're kind of close together here. And then we have a pause. And what that means is that usually when we're looking at the QRS complexes here and here, if we would find the halfway point somewhere, it would be here. So this QRS, if it was normal, it would be right here and would have the same shape as these other regular beats. But now because it's premature, this PVC here occurs early in the cycle. So this next beat that we would have here is basically happening earlier. So it's not in its regular spot that we would expect it in. Here's an example of a PVC in quadri-gemini, which means that every fourth beat is a PVC. So again, this wide and bizarre looking strange thing right here. And these are unifocal. See how they have the same shape. And then here we have an example of a patient who has an underlying what looks like a sinus rhythm by just looking at this normal beat here. And then we have several wide and bizarre looking beats here. So one of them is here, one of them is there, and then there's another one right there. And so this first one certainly looks different from the second and the third, but these two kind of look alike. You see how the shape is very similar. So this could be, this is definitely an example of multifocal PVCs, meaning that there's two or more cells in the ventricles that are irritable that are causing these irregular early beats. And see here, they give us an example of that marching out. I was just talking about in the other one with the R2R interval. So here is the QRS of this speed. Here is that one. Here is this one. And if we would measure the same distance out in between here, we would expect this QRS to be here. But we have this wide and bizarre looking thing here, meaning that it comes early in the cycle, earlier than we would have expected here. And this makes it a PVC. Causes of PVCs, they can occur in healthy people. So that can be somewhat normal, but they also can be caused by hypoxia and or stress or anything that increases our catecholamine release, digitalis, so the joxin toxicity can cause PVCs, as well as acid base imbalances and electrolyte imbalances. And we always worry about our potassiums and magnesiums here. And then certainly MI and CHF can also make the ventricles more irritable. Patient might be complaining of palpitations, a racing heart or feeling that their heart skipped they beat, and they might be complaining of chest or neck pain. Interventions for PVCs, sometimes none are required, and they will depend on the signs and symptoms and of the types of PVCs. So again, multifocal or coupled or PVCs that occur multiple in a row are more dangerous than one PVC every five minutes, for example. So they may or may not require any treatment. Oxygen, a lot of times, can be very helpful in resolving PVCs. And that just means that there is some sort of oxygen deprivation going on in the heart, and some supplemental oxygen will help. And then certainly if the patient is having a myocardial infarction, we need to follow advanced cardiac life support protocol to treat the patient appropriately with medications that are outlined in that protocol. And if there is an underlying cause, certainly we'll have to investigate what is going on. Is it an electrolyte imbalance, an acid base imbalance, or maybe does the patient have fluid volume excess from congestive heart failure? And then here is some credits and references for practice strips that I highly recommend you doing and looking into. And then here are the other videos in the EKG interpretation playlist, particularly the ones that go into the ventricular dysrhythmias, specifically ventricular tachycardia that I said can follow a run of PVCs. And then ventricular fibrillation as well as postless electrical activity and asystole. Thanks for watching Nursing School Explained. I'll see you soon.