ECG interpretation is an important skill that you want to have and in this comprehensive video I'll cover some of the most important rhythms you'll need to know in nursing. First let's look at normal sinus rhythm. So in order to interpret an ECG you have to know what it should normally look like. So with sinus rhythm this rhythm originates from the SA node which is known as a sinoatrial node. And the SA node is really the beginning part of the electrical conduction system.
And this is where we want our heart rhythms to originate so we have a normal rhythm in our patient. Now, how do we know that we have normal sinus rhythm? Well, let's look at these characteristics and criteria that tells us that we're dealing with normal sinus rhythm.
When you look at the ECG waveform, you should note the P waves and there will be P waves present in front of every QRS complex and they should be upright, measure less than 0.12 seconds, and this tells us about the atrial rhythm and rate. So the atrial rhythm for normal sinus rhythm should be regular and the rate should be anywhere between 60 to 100 beats per minute. Also, when you look at the PR interval, it should measure between 0.12 to 0.20 seconds. And if it measures greater than 0.20 seconds, you could be dealing with a heart block. Then when you look at the QRS complexes There should be one present after every P wave and they should measure no more than 0.12 Seconds now this tells us about the ventricular rhythm and rate So a normal sinus rhythm the ventricular rhythm should be regular and the rate should be 60 to 100 beats per minute It should actually be the same as the atrial rate There should also be a normal QT interval anywhere between 0.36 to 0.44 seconds.
And there should be a normal T wave after each QRS complex that should be round and upright. And then finally, the ST segment should be flat, hence isoelectric. So whenever you're looking at your patient's heart rhythm and you see that they meet all that criteria for normal sinus rhythm, that is a good thing.
This is a normal rhythm and it requires no treatment. Therefore, as a nurse, you want to just continue to monitor your patient by looking at those telemetry strips, looking at the cardiac monitor if they're on one, just to make sure that they're not deviating from this rhythm. Because many times patients do.
They may go into atrial fibrillation or sinus bradycardia or sinus tach, or they develop a heart block where that PR interval is prolonged. Next, let's look at sinus bradycardia. Sinus bradycardia is a rhythm that originates from the SA node, which is known as a sinoatrial node. However, this rhythm is a slow rhythm and let the names of these rhythms help you.
Brady means slow and cardia means heart. So we have a slow heart. And with bradycardia, what you have is a rate of less than 60 beats per minute and it's regular.
So what are the characteristics and criteria that tell you you're dealing with sinus bradycardia? Well, when you look at the rhythm, you're going to see that it has all the normal findings within its waveform as normal sinus rhythm, but it's going to be slow. So whenever you look at the P waves, they're going to look normal.
And our P waves tells us about the atrial rate and rhythm. So the atrial rate is going to be slow, less than 60, but the rhythm is going to be regular. Also, the QRS complex will be normal.
It will measure less than 0.12 seconds. And the QRS complex tells us about the ventricular rate and rhythm. So the ventricular rate will be less than 60. It should actually be the same as the atrial rate and the rhythm will be regular.
Furthermore, the PR interval will be anywhere between 0.12 seconds to 0.20 seconds. It will also have a normal T wave and a normal QT interval. But it is important to note. that the slower the rate the longer the qt interval could be because whenever your rate's slower it makes that qt interval a little bit longer so a big thing what you want to remember about sinus bradycardia is that it is slow and it's going to be regular. Now let's look at the causes of sinus bradycardia.
What could cause the heart to beat at a slow rate? Well, there are many causes of this. So to help us remember those causes, let's remember the word slow rates. S is for sick sinus syndrome. This is a condition where that SA node is damaged so severely that it can't work as the pacemaker of the heart.
So the heart doesn't beat very fast. It actually beats at a slow rate. And this condition can lead to other dysrhythmias as well.
such as like sinus arrest or brady tacky syndrome l is for low thyroid hormone o is for older adult so as we get older so does our sa node and whenever it gets older it will cause our heart to be at a slower rate so that's why you may find that older adults have a naturally slower heart rate. W is for weak and damaged heart muscles. So if that patient has experience of myocardial infarction where there's been severe ischemia to that heart tissue, it can damage the SA node because of that decreased blood supply. Also conditions that inflame or infect the heart like pericarditis can damage this area as well.
Then we have R for raised intracranial pressure. So a part of Cushing's triad actually is a slow heart rate. So if your patient has a slow heart rate, the respirations are irregular, and they have a widened pulse pressure, you want to think, okay, we have some issues with our intracranial pressure.
A is for athletes. So people who are very well conditioned, their heart will be at a slower rate. T is for toxicity of certain medications. So you want to be on the lookout for this group of drugs that could slow your patient's heart rate.
One group is called beta blockers and their generic names end in O-L-O-L like metoprol. Another group is calcium channel blockers, for example, verapamil. And another drug is digoxin.
So remember, whenever we give digoxin, we also want to check the apical pulse and you don't want to give digoxin if the apical pulse is less than 60. E is for electrolyte imbalances, so severe cases of hyperkalemia where that potassium level is very elevated. It could cause bradycardia. And then lastly, stimulation of vagal response where it's either overactive or the patient is having vomiting. It can cause a patient to brady down. So now let's talk about the treatment for sinus bradycardia.
Well, with this rhythm, it doesn't always require treatment. It depends on if your patient's having symptoms or not. So look at your patient, assess them, ask them questions, because you will know if they're having symptoms associated with this rhythm.
And some symptoms you want to look out for is you want to make sure that they're not hypotensive, that they're not having shortness of breath, chest pain, really fatigued, they're getting clammy and sweaty. That's telling you your heart's not perfusing and you need help. But if they're not having symptoms, like let's say they're a well-conditioned athlete or they're an older adult who's just had a heart attack, had their SA node age so they beat it a little bit of a slower rate usually in the 50s and they don't have signs and symptoms you just want to continue to monitor them but let's say you have that patient that's having signs and symptoms what do you want to do well you want to activate the emergency response system wherever you're at and get your patient treatment now treatment revolves around what's causing the sinus bradycardia so we'll find the cause and fix it for instance let's say they've had too much of a calcium channel blocker that dosage is just way too high for them we can stop it and hopefully that will correct it. Or if they have an electrolyte imbalance, we can fix it. Now some other treatments that can be given are like medications.
And to help you remember those meds that can help increase that heart rate, remember AID, A-D-E. So you can give them atropine, dopamine, or epinephrine. Now some other things that can be done is we can give them temporary pacemaking.
So give them a temporary pacemaker to help pace that heart. And if they're really bad off, they can give them a temporary pacemaker get a permanent implanted pacemaker to help them with their heart rate. Now let's look at sinus tachycardia. Sinus tachycardia is a rhythm that originates from the SA node, known as the sinoatrial node. So whenever you look at this rhythm's name, let the name help you.
Tachy means fast and cardia means heart, so we have a fast heart. With sinus tachycardia, the heart is beating at a fast rate, usually greater than 100 beats per minute, but it is regular. Now what are some characteristics and criteria? that tells you you're dealing with sinus tachycardia. When you go to look at the rhythm on the ECG, you're going to see that it has all the normal findings within the waveform as normal sinus rhythm, but it's going to be fast.
You're going to see that it has normal P waves and our P waves tells us about the atrial rate and rhythm. So the atrial rate will be fast, greater than 100 beats per minute, and its rhythm is going to be regular. The QRS complex is going to be normal.
It should measure less than 0.12 seconds and you're actually going to notice it'll appear narrow, especially if the rate is fast. And our QRS complex helps tells us about the ventricular rate and rhythm. So the ventricular rate is going to be the same as the atrial rate, greater than 100 beats per minute, and the rhythm is going to be regular.
Furthermore, the PR interval should be normal, anywhere between 0.12 seconds to 0.20 seconds, and the T wave will be normal along with the QT interval. But it could be on the shorter side, that QT interval, because the rate is fast. The faster the rate, the little bit shorter it's going to be.
But overall, the big takeaway with this rhythm is that it's going to be fast, greater than 100 beats per minute, and it's going to be regular. Now let's talk about the causes of tachycardia. What can make your heart beat very fast? Well, there are a lot of causes. So to help us remember those causes, let's remember the phrase tachy hearts.
T is for temperature elevation. So whenever your patient has a high fever, it increases the oxygen needs of the body. So to meet those needs, it causes your heart to be at a fast pace. faster rate in hopes of meeting those oxygen demands.
A is for aerobics. So any type of aerobic exercise will increase that heart rate, which is a good thing. We want to exercise that heart out sometimes.
C is for cardiac disease. So if a patient has a severe form of cardiac disease like with congestive heart failure or they've had a myocardial infarction that has really just damaged that heart it can cause that heart to beat at a faster rate and we really got to watch it because if the heart is beating too fast it can actually get too tired and it could lead to cartogenic shock. Then we have H for hyperthyroidism. So in these patients sometimes sinus tachycardia may be their only symptom. They go to the doctor, they can feel their heart flying in their chest and they check their thyroid levels and it's elevated.
Y is for Yelp, which means pain. So sometimes whenever patients are having pain that they cannot tolerate, their heart rate will go up. So this is one of those indicators to us as a nurse that we need to be looking to see, okay, I don't know of any other reason this patient is having this tachycardia.
Think maybe your patient's in pain and they need their pain treated. And this is especially true for patients who can't communicate pain to you. Maybe they're nonverbal or they're in a state where they can't tell you. H is for hemorrhage or hypovolemic shock.
So one of the last ditch efforts during these things where a patient's bleeding out or having low fluid status is that the heart will increase in its rate in hopes of just trying to pump out more blood. But in the end, it won't be able to do that unless we treat it. E is for emotional stress slash fear. A is for anemia.
And again, just trying to meet those oxygen demands. Then we have R for respiratory conditions like pulmonary embolism, pneumothorax, chronic lung disease where the oxygen is decreased. T is for therapeutic.
So medications can increase the heart rate. like atropine, albuterol, dopamine, epinephrine. So if your patient is tachycardic, look at their medication history, see if they're taking any of these, especially if they've maybe had an albuterol breathing treatment that can increase the heart rate.
And then lastly, stimulants can do this like nicotine, alcohol, cocaine, caffeine, and amphetamines. Now let's look at the treatments for sinus tachycardia. So the thing with this rhythm, it doesn't always require treatment because it could just be the result of something that the patient's doing.
For example, exercise. We want the heart rate to get up during exercise. That gives you a good cardiovascular workout.
But whenever we take that exercise away, the heart rate goes down. Or if the patient's just extremely stressed, it can cause their heart rate to go up, but we remove that stress, it goes down. So in those cases, whenever you can take it away and fix it, it's good to go.
But sometimes that's not the case and it does require treatment. Therefore, whenever this is the case, we want to identify the cause and treat it. And there's different types of tests that can be ordered to help us identify the cause. So one type of test is like cardiac tests. This can include a stress test, an echocardiogram, or a Holter monitor.
This is a cardiac monitor that the patient wears and then they turn it in. A cardiologist looks at their rhythm and tries to determine, hey, what's going on with your heart rate? We can also order labs to look at the thyroid levels, make sure they don't have heart.
hyperthyroidism. or look at the blood levels, rule out anemia, or any type of infection. So look at that white blood count.
Is it greater than 10,000? Could indicate infection, which could increase the heart rate. And then we want to look at that medication history because they could be taking a medication that increased their heart rate or using a substance that does that. In addition to that, medications can be ordered to help slow down the rate. And there are several groups of medications that could help slow the heart rate down.
One group of medications is called beta blockers. And these medications or generic name tends to end in O-L-O-L, for example, like metoprol. Also, calcium channel blockers could be ordered like verapamil or deltiazem to help slow that heart rate down. And then sometimes the patient just simply needs some pain medication to help treat that pain to decrease the heart rate or antipyretics for fever. Our next rhythm is atrial fibrillation.
So AFib is one of the most common rhythms you're going to see in a hospitalized patient. And what's occurring with this rhythm is that the atria are not beating like they should. Instead, they're beating at a very fast, irregular rate. And what's happening, in a sense, is that those atria are just quivering.
And whenever they quiver, they don't pump blood very well. Instead, blood just pulls in there, which could lead a blood clot to develop, which could eventually lead the patient to have a stroke. Now, how can you tell that your patient is in AFib? Well, let's look at the criteria and characteristics for this rhythm. When you look at the ECG waveform, you're going to see that P waves are not present before the QRS complexes.
Instead, the P waves are replaced with these irregular fibrillatory waves, which we call F waves. And they can be either described as being fine or coarse, depending on their amplitude. Now, because of this, you can't count the atrial rate.
But if you could, the atrial rate would be really fast and irregular. It would be greater than 400 beats per minute. Now, when you look at the QRS complexes, they will be...
present and they should measure less than 0.12 seconds. Now our PRS complex tells us about the ventricular rate and rhythm. So the rhythm is going to be irregular and the rate can be anywhere between being normal or it can be fast, greater than 100 beats per minute. Now if it's greater than 100 beats per minute, it's termed uncontrolled AFib and whenever this occurs, significant complications can happen because that heart is just beating way too fast. It's not pumping like it should.
Therefore, heart failure can develop if we don't get this rate under control. And if the rate is less than than 100 beats per minute this is considered controlled afib and because of the presentation of this rhythm you cannot measure the PR interval or the QT interval now what are the causes of afib well it can happen after heart surgery a lot of times after a person has some procedure on their heart it can cause them to enter this rhythm or they have some significant heart problem like they have a valve problem especially problems with the mitral valve or they have coronary artery disease they've had a heart attack or pericarditis. Plus lung conditions can affect this especially like COPD. And further studies have shown that patients who have sleep apnea are at risk for developing atrial fibrillation. So we definitely want to make sure we're screening patients for sleep apnea because they may be at risk for this abnormal heart rhythm.
So what's the treatment for AFib? Well it really depends on the patient. Are they having symptoms? Are they stable or unstable? Is this patient having symptoms?
having controlled or uncontrolled AFib. So if the patient is stable, meaning they have no symptoms and it's controlled, so it's less than 100 beats per minute, we want to make sure that we continue to monitor them and that that rate stays controlled. And then notify the doctor for further orders if needed and if the patient's condition becomes unstable. But let's say that the patient is unstable. Their blood pressure is dropping.
They have decreased cardiac output. You can tell that this heart is just not able to maintain perfusion. Plus, they have an uncontrolled rate.
Well, they're going to need a procedure called a synchronized cardioversion. And with a cardioversion, it's going to deliver a shock synchronized with the patient's R-wave and convert them back to normal sinus rhythm. Now before the cardioversion, you want to know how long the patient's been in afib because they may need anticoagulation prior to having the cardioversion to prevent blood clot problems. And many times before a cardioversion, a TEE will be performed, which is a transesophageal echocardiogram. And it is where they use ultrasound.
They go through the patient's mouth, down through the throat, and they will go behind the heart through like the esophagus. And they can take pictures of the heart and see if there are any blood clots present in the heart. And if the patient doesn't have a blood clot, they can be cardioverted. Now, after the cardioversion, patients may need for several weeks after the procedure some type of anticoagulation to prevent any blood clot problems. Now, patients can also be cardioverted through pharmacological methods instead of through electrical methods.
And medications that can be used for that are like Cartazine, which is known as Deltiazine. Also, Adenosine, Amiodarone, or other types of medications. And then some other medications that can be used that you want to be familiar with as a nurse are those anticoagulants. One type is warfarin, also known as Coumadin.
And this is just going to help with clot formation, preventing that. And then the patient can be prescribed beta blockers, for instance, like propranolol or calcium channel blockers, deltiazem and pilform, just to help maintain a normal rate and rhythm. And then sometimes the patient needs further treatment because sometimes it just doesn't work very well.
The patient continues to go in atrial fibrillation. So they may consider doing an ablation. And an ablation is a procedure that ablates, hence that word means destroys or erodes, some of the tissue in the heart to prevent it from abnormally firing like this in the future. Another rhythm is atrial flutter.
Atrial flutter, also referred to as a flutter, occurs because there is an abnormal electrical signal causing the atria to contract very rapidly. Now atrial flutter is similar to atrial fibrillation that we talked about in the previous review, but there are some differences that you want to be familiar with. So what are some characteristics and criteria to tell you that you're dealing with a flutter?
Well whenever you look at that ECG waveform you're going to see that there are no P waves but flutter waves that look like a sawtooth. And the atria are firing very rapidly, typically around a rate of 300 beats per minute, give or take, and its presentation will be regular. Now, it's important to note that these waves that you see in front of the QRS complex are not P waves, but abnormal P waves that we term flutter waves, and they have this sawtooth appearance.
Now, this sawtooth appearance is one of the key points in helping you discern atrial flutter from atrial fibrillation. Now when you look at the QRS complex, it should measure less than 0.12 seconds and our QRS complex tells us about the ventricular rate which can vary it can be regular or irregular but we don't want it to be too fast or too slow because this will affect how the heart can pump out blood hence our cardiac output and in this rhythm you cannot measure the PR interval or the QT interval or assess the T waves now what can cause atrial flutter well anything that really affects the heart especially a heart valve problem where we have the tricuspid and the mitral valve involved Or if the patient's had a myocardial infarction, a heart attack, it can cause this rhythm. Or if they've underwent heart surgery. Plus, if they have an overactive thyroid, it could lead to atrial flutter. Now, how do we treat atrial flutter?
Well, we really want to control that heart rate. And we can do that by administering medications. And some medications include calcium channel blockers, such as deltiazem, also known as cardiazem. or administering beta blockers.
One type is like propranolol or digoxin, especially if the patient has heart failure because it'll help that heart pump more efficiently where it's weak from the heart failure. And we can give antiarrhythmic drugs like amiodarone. And one thing we really want to do with this rhythm is we want to prevent a blood clot from forming because those atria are not contracting as they should. and blood can pool there.
And whenever we have blood pool in the heart, it could lead to a blood clot. So the patient may be on some anticoagulants such as warfarin. or also known as Coumadin to help prevent this.
Now if this rhythm is persistent and the patient starts to develop symptoms where they become unstable, we can do a synchronized cardioversion. And this is where a shock is synchronized to the patient's R-wave. So we will hopefully convert them back into normal sinus rhythm. And then finally, some patients need a procedure called an ablation.
And this is a procedure that ablates, and that word means destroys or erodes, some of the tissue in the heart to prevent it from firing out. abnormally. Next, let's look at ventricular tachycardia.
What is ventricular tachycardia? Well, it's an abnormal heart rhythm that originates from the ventricles, hence why we call it ventricular tachycardia. And the reason that this rhythm is occurring is because electrical conduction system is sending out an abnormal electrical signal that is causing those ventricles to just contract very rapidly.
And the problem with this rhythm is that these ventricles cannot pump blood out efficiently through the heart. And if it can't do that, cardiac output cannot be maintained. So we really want to correct this as soon as we notice it.
Now one thing you want to remember about this rhythm is that it can be short in duration and quick. For example, a patient can have a bunch of premature ventricular contractions, also known as PVCs together, like three or more in a row and we refer to this as VTAC. Or this rhythm can be sustained where it's just continuing.
So what are some characteristics and criteria that tell you that you're dealing with ventricular tachycardia? Well, the hallmark finding in this rhythm will be its QRS complex and the QRS complex is really the star of this rhythm It's really easy to identify because the QRS complex is going to be really wide It's going to be greater than 0.12 seconds and it's going to look bizarre Therefore, because of this, the ventricular rate is going to be very fast, anywhere between 100 to 250 beats per minute, and the rhythm is going to be regular. Because of this, you really can't assess the T wave. In addition, you can't assess P waves either. So you won't be able to determine the atrial rate or its rhythm or assess the PR interval.
And as you can see here in this rhythm, what really catches your eye is this bizarre looking QRS complex. It's very wide. it's regular and you can see that it's very fast. You can't really see any P waves, no PR intervals or T waves. And here, this is a classic example of ventricular tachycardia.
Now, a couple things you want to remember about VTAC is that it can have various presentations. VTAC can appear monomorphic and refer to this as monomorphic VTAC. And this is where its presentation is the same throughout. or it can appear as polymorphic and we refer to this as polymorphic VTAC. And this is where the rhythm does not look the same throughout but it's different.
And one type of polymorphic VTAC is called torsades de plant. And you want to be aware of these different presentations because treatment is slightly different for each. Now what can cause VTAC?
Well, if a patient is having abnormal electrolyte levels, especially abnormal potassium like hypokalemia, it can lead to this. Or if a patient has had a myocardial infarction where there's a lot of damage to that heart tissue, which will affect how that electrical conduction system can work. Plus medication toxicity can lead to this like DIG toxicity.
Or if a patient has heart disease, specifically like heart failure, coronary artery disease, or some type of valve disease. But now let's say that your patient is in polymorphic V-tach such as torsades of plant. What?
What could cause this rhythm? Well, one of the most common causes is that the patient is taking a medication that prolongs that QT interval, such as amiodarone, sodol, or procanamide. So you wouldn't want to give your patient these medications for treatment of this rhythm.
In addition, a low calcium, magnesium, or potassium level can cause it. Now let's talk about the treatment for VTAC. So with this rhythm, it requires immediate attention because it could easily progress to ventricular fibrillation, which will lead to death.
Now, depending on where you're at, how your patient is doing, are they stable, unstable, they don't have a pulse, you want to get help. So some things you want to do is you want to activate the emergency response system, you want to get supplies like crash cart, defibrillator, and you want to follow ACLS protocol. So let's say that your patient is stable, meaning they have no symptoms and they have a good pulse. What can be ordered is like an antiarrhythmic medication such as amiodarone IV. And if this doesn't convert them to normal sinus rhythm, what could be considered is synchronized cardioversion, which will help put that patient back into a normal rhythm.
But let's say that your patient is unstable, meaning they're having symptoms, but they still have a pulse. So their symptoms are revolving around decreased cardiac output because whenever that heart is pumping like this, especially those ventricles, it's not pumping very well. So cardiac output will fall.
So you'll start to see hypotension, mental status changes. That pulse will be there, but it'll be weak, they'll be cool and clammy, and they can have chest pain. So what can be ordered for this is that synchronized cardioversion can be used, where we can put them back into a normal rhythm, and then follow it up with an antiarrhythmic-like amiodarone.
But now let's say we have worst-case scenario. Our patient is in this rhythm, but they have no pulse. Well, what you want to do is you want to start CPR immediately.
So you'll be doing chest compressions, defibrillation. giving epinephrine and then other medications can be given throughout that time where you're doing chest compressions and defibrillating Such as like amiodarone or lidocaine and then in addition you want to be securing that airway Now in regards to treatment for like let's say a polymorphic VTAC like torsades One thing that can be given is magnesium sulfate and then stopping any medications that prolong that QT interval So you would not want to give the patient amiodarone or prokandamide because those increase that QT interval. And of course, if the patient is unstable, has no pulse, you'd want to treat it like V-fib with CPR and defibrillation. And then once the patient is converted back to a normal rhythm, it may be necessary that they get an implanted ICD, which is a cardioverter defibrillator to prevent any further episodes of this happening again. Now let's look at ventricular fibrillation.
What is V-fib? Well, this is a rhythm that originates from your ventricles and the ventricles are really important for helping you squeeze blood out of Your heart and maintain cardiac output So with this rhythm what happens is that there's an abnormal electrical signal causing those ventricles to really just quiver They are not pumping and squeezing that blood out like they should So because of this, what will happen is that cardiac output will fall. So this rhythm is deadly. And if it is not reversed or treated, the patient can die within minutes. So what are some characteristics and criteria that tells you that you have ventricular fibrillation?
Well, this rhythm is fairly easy to identify. It has a chaotic, rapid rhythm that has no organization to it. Instead, what you see on that ECG strip is fibrillatory waves that can vary in size.
This means that they can be coarse fibrillatory waves. And whenever you see this, it means that the patient may have a better chance of being revived. Or you can see fine fibrillatory waves, which is similar to a flat line, which we refer to as a systole.
And whenever you see these fine waves, the chances are getting slim for that patient to be revived. And then of course due to the nature of this rhythm, you're not going to be able to see P waves, QRS complexes, T waves, PR intervals, or anything like that. And here on this strip, you can see a classic example of ventricular fibrillation. This is actually coarse fibrillatory waves.
And again, notice you cannot find P waves, QRS complexes, T waves. Really what it looks like is just a bunch of squiggly lines on the ECG strip. And these lines are being produced from our ventricles which are just setting in the chest quivering.
They're not contracting like they should. Now what can cause V-fib? Well, anything that affects the heart, especially heart disease. So if the patient has severe heart disease, let's say they have a severe heart attack, this could cause V-fib because with a heart attack you can get ischemia. that can damage the heart muscle so much that will cause it not to pump efficiently and it can lead to this rhythm.
Plus any type of electrolyte imbalances especially ones that affect potassium levels. So we have severe low or high levels that could cause V-fib. In addition, hypoxia can lead to this, which is where we have low levels of oxygen in the blood.
And there's a lot of diseases that can cause low levels of oxygen in the blood, especially diseases that affect the respiratory system. And then lastly, drug overdose can lead to this rhythm as well. Now let's talk about the treatment for V-fib.
So again, as I said earlier, this rhythm is deadly. So your patient isn't going to survive very long without treatment and they're going to be unreliable. responsive they're not going to have a pulse so what you want to do is you want to get help immediately so call a code or activate the emergency response system in your area and you want to start cpr immediately and follow acls protocol so you're going to be doing chest compressions defibrillation giving epinephrine and other medications like amiodarone lidocaine and securing that airway And then if the patient is successfully resuscitated, it may be necessary to consider an implanted ICD, a cardioverter defibrillator, to help treat any further episodes in the future.
Our next rhythm is a systole. A systole occurs when there is no contraction in the heart. And whenever you look at the word, look at the letter A.
That means without, and systole means contraction. So whenever you put that together, we have no heart contraction. Now what are the characteristics and criteria to tell you that you're dealing with a systole? Well this rhythm is actually one of the most easiest rhythms to identify out of all the rhythms you have to know as a nurse.
And what it looks like is a flat line on the ECG and there's no ECG waveform so you're not going to see a PQRST on there at all. And the ECG, those electrodes, are not picking up any heart contraction from the atria or the ventricle. So that tells you that this heart is not pumping. Now the thing about this, whenever you see a flat line on an ECG, you want to immediately check your patient. Always check them, check their pulse, and make sure everything is plugged in and attached.
Because if those telemetry wires become unplugged or an electrode isn't sticking right, or you have a bad connection, it can present as a systole and you don't truly have it. So always check your patient. Now what can cause a systole? Well really anything that leads to death and many times what happens is that this patient is in a lethal rhythm like V-tach or V-fib and it's untreated and it progresses to a systole where this heart is quits contracting. So whenever we take ACLS to help prepare us for these situations, we're taught the H's and the T's.
So you want to be looking at those H's and T's as potential causes for this rhythm. And some of those include like hypothermia, hypovolemia, hypoxia, toxins, thrombosis, tension pneumothorax, and so forth. So what is the treatment for a systole? So as a nurse, whenever you find your patient in this, you want to confirm that this is a systole.
Check that pulse. And if you have no pulse, you want to immediately activate the emergency response system. If this is calling code blue, do that.
Call 911. Whatever steps you need to take. Then you want to start CPR immediately. And then you want to check the rhythm per ACLS's recommendation. And asystole is not a shockable rhythm. So we cannot defibrillate this rhythm.
So you want to continue doing CPR, doing rhythm checks per protocol. Then some things that can be given, you can administer epinephrine, you want to support that airway. And then of course, as you're continuing CPR and rhythm checks, you're going to be checking those H's and T's, thinking about what could be causing this. Another rhythm you'll want to know is PEA, which is pulseless electrical activity.
PEA is a rhythm. that whenever you look at the ECG, you will see organization to it. And what you will see in terms of organization can vary on the ECG. You can see P waves with QRS complexes, which makes it look like normal sinus rhythm, sinus tach, or sinus bradycardia. And this makes its appearance seem like a normal finding.
But it's anything but normal because whenever you go to check your patient, your patient will be unresponsive. They will not have a pulse and they won't be breathing. Therefore, PEA is a life-threatening rhythm and it indicates that your patient is in cardiac arrest.
Therefore, as a nurse, it's always important that you check your patient. You feel that pulse to confirm your findings with what you're seeing on that ECG reading. Now what causes PEA? Well one big cause is hypoxia where the patient doesn't have enough oxygen in the blood.
Another cause is hypovolemia like hypovolemic shock or an electrolyte imbalance where The potassium levels being affected where we have hypo or hyperkalemia or the patient has a blood clot like Thrombosis or they've experienced some type of trauma or cardiac disease now What is the treatment for PEA? So as a nurse after you've confirmed that you do have PA you want to immediately Activate the emergency response system call code blue call 911 and start CPR immediately So you'll be doing CPR. You'll have a team of people helping you and you'll be doing rhythm checks per ACLS's recommendations to see what kind of rhythm you have.
Now one thing you want to remember about PEA is that it is a non-shockable rhythm. We cannot shock this rhythm so we'll just continue CPR until we have a rhythm that we can shock. Now some medications that can be given are like epinephrine and we'll be supporting the airway throughout this and throughout this time of trying to resuscitate this patient, we'll be thinking of the H's and the T's.
What could be causing this PEA? For instance, is it hypovolemia? Is it hypoxia? Is there toxins involved?
Do we have a clot like thrombosis? Is there a tension pneumothorax? And so forth. And finally, let's look at the different types of AV heart blocks. And the reason heart blocks occur in the heart is because there is some type of block in the electrical conduction system.
Now there's various types of heart blocks you want to be familiar with. And these types include first degree heart block, second degree heart block, and there's a couple of these. There's a second degree type one, which has several names.
It's sometimes referred to as Mobitz type one or WinkyBock. And then we have second degree type two, which is sometimes referred to as Mobitz type two. And then lastly, we have the complete heart block, which is referred to sometimes as third degree heart block.
So first, let's take a look at first degree heart blocks. So whenever you go to analyze this rhythm, you may think at first that you have some type of sinus rhythm. But whenever you take a closer peek, you will see that it has a subtle little secret.
It actually has something up with its PR intervals. The PR intervals will be prolonged, hence they will be lengthened. And with this rhythm, the PR interval will be greater than 0.20 seconds, and this will occur regularly throughout the rhythm. And the reason that this is occurring is because electrical signal is able to go down through the atria to the ventricles, so you get the P wave and the chioris.
complex but it is doing this slowly through that AV node which creates that longer PR interval. So what are some characteristics and criteria this rhythm must have in order to be a first-degree heart block? Well whenever you look at this rhythm it's going to look very similar to normal sinus rhythm. The P waves are going to be normal.
The rhythm of the P waves which looks at our atrial rate will be regular. It can have a rate between 60 to 100 beats per minute and then sometimes these rhythms can be a little bit slower. So you may see sinus bradycardia with a first degree AV block.
In addition, the QRS complex is going to be normal. It's going to measure less than 0.12 seconds and the QRS complex represented our ventricular rate. So our ventricular rate can be anywhere between 60 to 100 beats per minute or slightly slower and it's going to be regular. In addition, you're going to have a normal QT interval.
But when you go to measure the PR interval, it is going to be prolonged. It is going to be greater than 0.20 seconds. And as you can see with this rhythm here, we have a prolonged PR interval.
That is the only difference between this and a sinus rhythm is this interval. Now to help you remember this heart block from all the other heart blocks you have to know, remember we are dealing with first degree heart block. First means one, so we're dealing with really one big problem with this rhythm.
We have a prolonged PR interval that is occurring regularly throughout the rhythm. Now what causes first degree? AV heart blocks. Well, this can actually be normal in some patients and we'll continue to monitor it.
It can also be caused by a myocardial infarction or certain medications such as calcium channel blockers, beta blockers, and digoxin. Now, what is the treatment for a first degree heart block? Well, typically patients don't have signs and symptoms with this type of rhythm. And usually the only reason we know that a patient's in a first degree heart block is because they had a routine EKG where we could actually see it, or we put them on a heart monitor and we could see the rhythm. and see that prolonged PR interval.
So we'll just continue to monitor them, make sure they don't advance to another type of heart block or another type of abnormal rhythm. And if the patient has an extensive heart history, they may need to be further evaluated by a cardiologist. Plus, let's say they're on some type of medication that can do this that I listed earlier.
Well, those medications may need to be adjusted and this heart rhythm may resolve itself. Next, let's look at second degree type 1 heart blocks, also known as Mobitz type 1 or Winky Box. Now the reason that this rhythm is occurring is because that electrical signal that's going from the atria to the ventricles is getting progressively slower until it doesn't really stimulate the ventricles to contract. hence produce a QRS complex. So all of a sudden we will drop a QRS complex.
Therefore, the key to help you really understand this heart block from all the other types of heart blocks is that that PR interval is going to gradually start lengthening. So whenever you look at that rhythm, you're gonna notice that the P wave is getting further and further away from the QRS complex. And then all of a sudden there's a P wave, but a missing QRS complex. And then the cycle is just gonna repeat itself again.
Therefore, whenever we look at the characteristics and criteria for this to be a second degree type 1 heart walk you're going to see normal looking p waves and the p waves tell us about the atrial rate and atrial rhythm so the atrial rate will be normal the rhythm will be regular but the hallmark is that we're going to have gradually longer pr intervals until we don't have a qrs complex behind a P-Wave and this cycle will repeat itself again. So whenever you do see those QRS complexes, they will look normal and they will measure less than 0.12 seconds, but some of those will be gone. And because of that, the ventricular rhythm will be irregular and the ventricular rate will be slightly slower than the atrial rate. Now what can cause this type of heart block? Well, a myocardial infarction can, especially an active MI that's affecting the inferior wall of the heart because it's causing acute ischemia that's depriving that heart tissue of that oxygen it needs to function.
In addition, medications can do this like calcium channel blockers, beta blockers, digoxin, rheumatic fever, and increased vagal tone. Now how is a second degree type 1 treated? Well, first of all, you want to assess your patient and see if they're having any symptoms.
If they're not, you want to continue to monitor them, and a cardiologist may be consulted just to further evaluate the patient. Sometimes they need medication stopped that slow that AV conduction system, such as the calcium channel blockers, beta blockers, digoxin, and that will help them. But you also want to evaluate your patient, make sure that they're not having a heart attack, an MI, and if they are, they need treatment immediately.
Now let's say your patient is having symptoms. They're presenting with signs and symptoms that shows you that they're having low cardiac output, that it's falling. The heart's not able to pump blood and maintain itself. So the patient's having mental status changes. They have a really weak pulse.
Their blood pressure is severely low. They're pale. They're dizzy.
All that's telling you, hey, my patient is not perfusing fast. Something's wrong. So with this, you want to activate the emergency response system wherever you're at.
And with this, sometimes what will be ordered is atropine or temporary paste. Now let's look at second degree type 2 which is also known as Mobitz type 2. So the reason that this rhythm is occurring is because electrical conduction system is not sending a steady signal. from the atria to the ventricles because whenever it normally does that we get a p wave followed by a qrs complex and because that signal is not steady we're going to actually lose that qrs complex therefore what you want to remember is that the pr interval does not progressively get longer and longer and then all of a sudden we drop a qrs complex that happens in second degree type one in second degree type two that pr interval is going to stay constant meaning it's going It's going to stay the same throughout that rhythm. And then we will lose a QRS complex at some point.
So whenever you look at the characteristics and criteria for this rhythm, you'll see the following. The atrial rate will be normal, 60 to 100 beats per minute, and the rhythm will be regular. That PR interval is going to be constant. It's going to stay the same.
And the PR interval can actually be normal or it could be prolonged. Now the ventricle rate will be slower, less than 60 beats per minute, and the reason for this is because we're missing some QRS complexes sometimes, which throws off our ventricular rate. And the rhythm of the ventricular rate will be irregular, again because we're missing some complexes. Now whenever you do see the QRS complexes sometimes they can be wide greater than 0.12 seconds or narrow less than 0.12 seconds and this depends really on where that block signal is within that conduction system. Now what are some causes of this type of heart block?
Well, an active myocardial infarction can cause this, especially one that's affecting the anterior wall of the heart. Advanced coronary artery disease followed by any type of structural damage to the electrical conduction system and then medications that slow the AV conduction system such as calcium channel blockers, beta blockers, digoxin, and so forth. Now, what is the treatment for this type of heart block? With this type of heart block, it is considered worse than the second degree type one that we discussed earlier. And the reason for this is because our ventricular ray is on the slower side and when we slow down the ventricular ray, it affects how much blood or heart can pump to our body and keep us alive.
Therefore, it lowers cardiac output and because of this the patient is more likely to have symptoms with this rhythm. So if a patient does have symptoms that correlate with low cardiac output like low blood pressure, weak pulse, they're getting cold, sweating, mental status changes, they need treatment. So some treatment includes temporary pacing and then insertion of a permanent pacemaker.
Now sometimes patients do have this rhythm, that ventricular rate is able to maintain their cardiac output, so they don't really have symptoms. So if that's the case, we would monitor them closely and consult with cardiology for further evaluation. That may include stopping certain medications to help with that AV conduction. Now lastly, let's look at complete heart blocks, also known as third degree heart blocks. This type of heart block is the worst of all blocks and the reason it's occurring is because electrical signal from the atria isn't Making it to the ventricles because normally remember whenever the atria contract it creates the P wave and then right after that we have ventricular contraction which creates the QRS complex So on an EKG strip you should have P wave QRS complex P wave QRS complex And that shows you that signals traveling from the atria to the ventricles causing contraction and it's working so well together but here in this rhythm you're gonna have P waves and QRS complexes that aren't collaborating hence working together they're really independent of each other so over here there will be some P waves they're doing their own thing and then QRS complexes who are doing their own thing therefore whenever we're looking at the characteristics and criteria to determine if this is a third-degree heart block you're gonna see the following regular P waves making that atrial rhythm regular and it's rate normal and the QRS complexes will be regular make the ventricular rhythm regular but there will be less of those QRS complexes than P waves so the ventricular rate will be slower than the atrial rate.
Now it's important to note that the ventricular rate can be 40 or less depending on what structure is firing for the ventricles causing it to contract. And when you measure those QRS complexes, the width can vary depending on what structure is firing. So they can be narrow or wide, so greater or less than 0.12 seconds. In addition, you can have variable PR intervals because, again, the P-wave and the QRS complexes are independent. Now, what could cause this type of heart block?
Well, the person could be born with it, so it could be congenital. Or the person has severe heart disease or they have a myocardial infarction or they're taking some type of medication that they've become toxic on like digoxin or they have structural damage to their heart that's affecting the electrical conduction system or there is a heart valve. problem.
Now what is the treatment for a third degree heart block? Well with this your patient's usually going to have some signs and symptoms because whenever the heart is beating like this those ventricles and atria they're really being independent of each other it's not going to perfuse your body so you're going to have a low cardiac output, which you can present with a low blood pressure, weak pulse, mental status changes. That patient just doesn't look good. They're pale, they're cold, they're clammy.
All of that's telling you, hey, that heart is not pumping enough blood throughout the body to keep it alive and this could progress to death. So what you want to do is you want to activate that emergency response system. And this will get a team in the room to help you. Now some treatment that can be given to that patient is that atropine can be administered to help that heart pump more efficiently, or the patient could be connected to a temporary pacemaker, which will again get that heart beating correctly so we can maintain cardiac output. And then eventually the patient will need a permanent pacemaker implanted.
Okay, that wraps up this video on heart rhythms you'll want to know. And if you want to see more videos on ECG interpretation, NCLEX reviews, and nursing skills, you can click click the link in the YouTube description below.