Excellent examples and explanations. They also are good examples of how polarity in aVR is most reliable way to distinguish SVT (QRS negative) from VT (QRS positive).
What is the cause of increased qrs voltage in lead v4 to v6. Also t wave inversion in v5 and v6. Left ventricular hypertrophy? Obstructive cardiomyopathy? Brugada syndrome?
The criteria for RBBB is a prolonged QRS interval (i.e. wide QRS), rSR' (i.e.M-shaped) complex in V1, and a wide S wave in the lateral leads (I, aVL, and/or V6). In this case the QRS complex isn't wide, so it's definitely not a complete RBBB. A reasonable thought would be that this represents an incomplete RBBB (i.e. RBBB except with a *relatively* narrow QRS) but the lateral S waves are not particularly wide and the M-shaped complex in V1 is primarily due to overlapping flutter waves. In other words, most of the initial r wave of the rSR' complex is actually a flutter wave.
Awesome lectures Dr. Eric. I appreciate your efforts in educating 1000s of students & residents. I have questions. Example 4 looks regularly irregular to me. Similarly the fast component of example 5 looks regular. Any comments/explanations?
+Alestar Bronson Thanks for the comment! You are absolutely correct about example 4 - it's a fascinating example of a-flutter combined with a probable Wenckebach phenomenon in the AV node, resulting in an apparently fixed 12:5 AV block. These types of very complex repeating patterns are seen on rare occasions. Although it's regularly irregular as seen from your close inspection of the EKG, on auscultation most people wouldn't be able to pick up the subtle repeating pattern and it would sound like it was irregularly irregular. (Not really sure what I was thinking when I labelled it irregularly irregular, but maybe that was it?). I've added an annotation to correct this. Regarding example 5, although from afar it appears regular, if you actually measure each RR interval, there is a bit of variability. I just asked a cardiologist how she would characterize the regularity (or lack thereof) of torsades, and her response was that it's just semantics that doesn't impact the diagnosis of this specific rhythm.
+Eric's Medical Lectures Thank you Dr. Eric. About example 5, the explanation clears it up. Though insignificant for this rhythm, my assumption about regularity in general was, variability of 1 - 2 small boxes would still be considered as regular interval, (respiration induced variability?) but I could be wrong. About example 4, I had to watch your video on Brady arrhythmias to understand your explanation. That’s what caused me the delay to reply. Keep impressing us with your awesome lectures. I am already a fan of you!
i cannot be grateful enough that you made these videos , i was almost about to give up on studying ekg but these videos helped a lot!! thank you so much
Having had 9 years to think about it ( ;) ), I still don't think the diagnosis can be made with certainty beyond saying it's an SVT vs. atrial flutter with 2:1 AV block, though I would agree that the former was much more likely. Junctional tachycardia is a form of SVT, but so is AVNRT and orthodromic AVRT - I think all are possible. It would require either a baseline ECG and/or provocative maneuvers to sort it out.
The patient does technically have left axis deviation, but the reason for that isn't LVH or any other primary myocardial (i.e. heart muscle) problem. Instead, the patient has a left bundle branch block, which gives the QRS complex the unusual appearance (e.g. tall broad R waves in I and aVL, deep broad Q waves in V1). Diagnosing LVH in the presence of a LBBB is trickier than it would be otherwise, and in the era of easily-accessible bedside ultrasound, most cardiologists don't bother thinking about it and just put an ultrasound probe on the chest to see it directly.
When you are assessing atrial activity, you need to consider all of the leads. Sometimes not all atrial activity will be evident in every lead. So one lead might only show atrial activity once per QRS complex, while another lead shows it twice. In the case of example 10, I agree that the atrial activity in lead III that immediately precedes the QRS looks like a conventional P wave - but only when viewed in isolation. There is another bump on the end of each S wave in that same lead. While one might speculate that to be a r' wave, RSr' complexes (i.e. the second r is much smaller than the first) are rare compared to rSR' complexes (i.e. the first r is much smaller than the second). But more importantly, other leads (e.g. V1) show an appearance to that end-of-QRS deflection that is more consistent with atrial activity.
It looks very regular to me in the video. Maybe there is aliasing artifact when playing it on your computer/monitor that's giving it an appearance of being slightly irregularity? Here is a png file of the original: imgur.com/gallery/17zrcyF (EDIT: Sorry, I misread your comment as EKG #7 not the EKG at 7 minutes)
@@-HappyLife Yes, you're correct. There used to be an on-screen annotation addressing this, but it was lost when UA-cam discontinued the annotations feature years ago. From a previous comment I left: "You are absolutely correct about example 4 - it's a fascinating example of a-flutter combined with a probable Wenckebach phenomenon in the AV node, resulting in an apparently fixed 12:5 AV block. These types of very complex repeating patterns are seen on rare occasions. Although it's regularly irregular as seen from your close inspection of the EKG, on auscultation most people wouldn't be able to pick up the subtle repeating pattern and it would sound like it was irregularly irregular. (Not really sure what I was thinking when I labelled it irregularly irregular, but maybe that was it?). I've added an annotation to correct this."
Hello, I'm in paramedic school currently learning about cardiology and EKG interpretation and your videos have given me a great head start towards understanding it. I do have one question though. When Example 9 came up, I went through the algorithm that was taught in my class (which is very similar to yours, except it focuses on atrial activity first) and I determined it was Junctional Tachycardia (from the narrow QRS complexes, regular rhythm of +100 beats/min, and lack of definitive P waves) as oppose to SVT or Atrial Flutter. I also learned that SVT is only indicated in a heart rate of +150 beats/min and that Atrial Flutter is characterized as having distinct flutter waves. I personally don't see any evidence of flutter waves and if there was any indication of P waves it would be in the precordial leads with a very faint morphology. I could also see in leads II, III, aVF, and V1 of what may look like a P wave buried in the QRS complex, but wouldn't that be caused by the junctional rhythm anyway? Thank you for your time
Jonathan Souther There is no specific cutoff of heart rate for an SVT. While SVTs are usually above 150, they don't need to be. Regarding this being flutter, it would be highly unusual for the flutter waves to be more visible in V5-6 than the inferior leads or V1, but it could be an atypical flutter (i.e. reentrant circuit using an unusual pathway), which could also explain why it's relatively slow for 2:1 flutter. While the EKG is theoretically consistent with junctional tachycardia, junctional tachycardia is a very rare rhythm in adults - essentially only seen in adults with significant congenital heart disease, and can be occasionally induced in the EP lab under very controlled circumstances. If you were playing the odds, I'd say that an unusually slow AVNRT is the most likely rhythm here, but it's far from certain. What I think you are referring to as P waves buried in the QRS complex in the inferior leads is just non-specific notching of the S wave.
An interesting notion - measuring HR in Hz. I agree that there may be situations in which this would make quick calculations a little easier. (though the word Hertz as the primary unit of frequency was named after Heinrich Hertz, not Herz - German for heart). Electrophysiologists actually often discuss heart rates in terms of "cycle lengths", which is the duration of time between successive QRS complexes (or P waves) in units of miliseconds. So a HR of 120 bpm might be described as "a tachycardia with 500ms cycle length".
In the last example... The reason for broad qrs complex?? SVT WITH ABERRANCY... I mean in this case SVT(atrial flutter) with aberrancy( previous LBBB).... Am I right... Pls correct if I am wrong
Yes, I agree, and good catch! The following is copied and pasted from another reply of mine elsewhere in the comments: "Thanks for the comment! You are absolutely correct about example 4 - it's a fascinating example of a-flutter combined with a probable Wenckebach phenomenon in the AV node, resulting in an apparently fixed 12:5 AV block. These types of very complex repeating patterns are seen on rare occasions. Although it's regularly irregular as seen from your close inspection of the EKG, on auscultation most people wouldn't be able to pick up the subtle repeating pattern and it would sound like it was irregularly irregular. (Not really sure what I was thinking when I labelled it irregularly irregular, but maybe that was it?). I've added an annotation to correct this. [the annotations feature was removed from UA-cam several years ago] Regarding example 5, although from afar it appears regular, if you actually measure each RR interval, there is a bit of variability. I just asked a cardiologist how she would characterize the regularity (or lack thereof) of torsades, and her response was that it's just semantics that doesn't impact the diagnosis of this specific rhythm."
But the last example *is* atrial flutter with 2:1 AV block + LBBB. I don't mention the LBBB because most viewers watch these videos out of order and may not know what a bundle branch block is yet.
@@StrongMed I thought I was wrong about the LBBB. I had to check the comment section to see if anyone else noticed. I'm glad I could distinguish that, thank you!
The atrial activity is occurring with a periodicity of 300 cycles/min, which is simply too fast for rhythms other than atrial flutter. However, there is a semantic argument as to whether atrial flutter should be placed into the general category of "SVT", and probably most physicians in the US do this without thinking too much about it. Cardiologists generally consider a-flutter (and a-fib) distinct from the supraventricular tachycardias on account of differences in treatment, and the fact that flutter is relatively easy to distinguish on ECG while the other/true SVTs (e.g. AVNRT, AVRT, atrial tachycardia) are relatively hard to distinguish from one another. For this series, I take the cardiologists' viewpoint and do *not* consider a-flutter a type of SVT.
hey Eric, in the last example, is not there a R R-prime pattern in V5 lead. This together with a marginally wide QRS makes up for LBBB. Can you please clarify? :)
Good pick-up! It's not the most classic LBBB ever (e.g. the R waves in I and aVL are usually more prominent, and QRS duration is usually more prolonged). I made this a few years ago (i.e. I might be misremembering), but I probably didn't mention it because some people watch these videos out of order, and I didn't want to confuse viewers by talking too much about bundle branch blocks when they might not be familiar with them.
In that case Eric, what points would suggest that this is NOT an SVT (given the irregular relationship of P waves withe QRS complex) with abberency (LBBB)? Thanks!
Absolutely fantastic. Such a high standard of teaching.
Excellent examples and explanations. They also are good examples of how polarity in aVR is most reliable way to distinguish SVT (QRS negative) from VT (QRS positive).
not my confidence being crushed at the last ECG
Thank you Doctor Strong !
excellent video
What is the cause of increased qrs voltage in lead v4 to v6.
Also t wave inversion in v5 and v6.
Left ventricular hypertrophy?
Obstructive cardiomyopathy?
Brugada syndrome?
awsome!
Hello doc, Had a doubt with Example 4. Is there a presence of RBBB as there is M shaped QRS is V1 and absent q wave in V6?
The criteria for RBBB is a prolonged QRS interval (i.e. wide QRS), rSR' (i.e.M-shaped) complex in V1, and a wide S wave in the lateral leads (I, aVL, and/or V6). In this case the QRS complex isn't wide, so it's definitely not a complete RBBB. A reasonable thought would be that this represents an incomplete RBBB (i.e. RBBB except with a *relatively* narrow QRS) but the lateral S waves are not particularly wide and the M-shaped complex in V1 is primarily due to overlapping flutter waves. In other words, most of the initial r wave of the rSR' complex is actually a flutter wave.
LOL that arbitrarily 99.5 % certainty joke at the end killed XD
Million thanks for the ECG quiz! You got me in the last one! :)
Awesome lectures Dr. Eric. I appreciate your efforts in educating 1000s of students & residents. I have questions. Example 4 looks regularly irregular to me. Similarly the fast component of example 5 looks regular. Any comments/explanations?
+Alestar Bronson Thanks for the comment! You are absolutely correct about example 4 - it's a fascinating example of a-flutter combined with a probable Wenckebach phenomenon in the AV node, resulting in an apparently fixed 12:5 AV block. These types of very complex repeating patterns are seen on rare occasions. Although it's regularly irregular as seen from your close inspection of the EKG, on auscultation most people wouldn't be able to pick up the subtle repeating pattern and it would sound like it was irregularly irregular. (Not really sure what I was thinking when I labelled it irregularly irregular, but maybe that was it?). I've added an annotation to correct this.
Regarding example 5, although from afar it appears regular, if you actually measure each RR interval, there is a bit of variability. I just asked a cardiologist how she would characterize the regularity (or lack thereof) of torsades, and her response was that it's just semantics that doesn't impact the diagnosis of this specific rhythm.
+Eric's Medical Lectures
Thank you Dr. Eric. About example 5, the explanation clears it up. Though insignificant for this rhythm, my assumption about regularity in general was, variability of 1 - 2 small boxes would still be considered as regular interval, (respiration induced variability?) but I could be wrong.
About example 4, I had to watch your video on Brady arrhythmias to understand your explanation. That’s what caused me the delay to reply. Keep impressing us with your awesome lectures. I am already a fan of you!
i cannot be grateful enough that you made these videos , i was almost about to give up on studying ekg but these videos helped a lot!! thank you so much
In ex.2, is there sign of stroke in v4’v5, v6? St elevation?
I disagree with #9 diagnosis. I think the rhythm for # 9 is Junctional tachycardia with a left anterior fasicular block.
Having had 9 years to think about it ( ;) ), I still don't think the diagnosis can be made with certainty beyond saying it's an SVT vs. atrial flutter with 2:1 AV block, though I would agree that the former was much more likely. Junctional tachycardia is a form of SVT, but so is AVNRT and orthodromic AVRT - I think all are possible. It would require either a baseline ECG and/or provocative maneuvers to sort it out.
Hello, thank you for your videos! Would you say there is also LVH and extreme left axis deviation in example 7?
The patient does technically have left axis deviation, but the reason for that isn't LVH or any other primary myocardial (i.e. heart muscle) problem. Instead, the patient has a left bundle branch block, which gives the QRS complex the unusual appearance (e.g. tall broad R waves in I and aVL, deep broad Q waves in V1). Diagnosing LVH in the presence of a LBBB is trickier than it would be otherwise, and in the era of easily-accessible bedside ultrasound, most cardiologists don't bother thinking about it and just put an ultrasound probe on the chest to see it directly.
Hi,nice video. in example number 2 there is significant ST elevation in V2 and V3 which looks like myocardial infarction. what do u think?
Yes, that's correct. Dr Strong did answer a similar question down below but it's a bit hidden
#10....visually, where is the distinction between atrial flutter and atrial tachy with 2:1 block???
Thank you Dr.Eric
Superb...as usual...thx prof
In the last example isn't there nice looking constant p waves in lead III.
So, why it not not sinus tachycardia with wberrancy?
When you are assessing atrial activity, you need to consider all of the leads. Sometimes not all atrial activity will be evident in every lead. So one lead might only show atrial activity once per QRS complex, while another lead shows it twice. In the case of example 10, I agree that the atrial activity in lead III that immediately precedes the QRS looks like a conventional P wave - but only when viewed in isolation. There is another bump on the end of each S wave in that same lead. While one might speculate that to be a r' wave, RSr' complexes (i.e. the second r is much smaller than the first) are rare compared to rSR' complexes (i.e. the first r is much smaller than the second). But more importantly, other leads (e.g. V1) show an appearance to that end-of-QRS deflection that is more consistent with atrial activity.
Thanks for this meaningful exaplanation. @@StrongMed
Actually the EKG shown at 7 minutes has a regularly irregular rhythm - please kindly double check and let me know
It looks very regular to me in the video. Maybe there is aliasing artifact when playing it on your computer/monitor that's giving it an appearance of being slightly irregularity? Here is a png file of the original: imgur.com/gallery/17zrcyF (EDIT: Sorry, I misread your comment as EKG #7 not the EKG at 7 minutes)
Hello. Thanks for getting back to me. I meant example 4. I think the rhythm in example 4 regularly irregular. Please kindly let me know.@@StrongMed
@@-HappyLife Yes, you're correct. There used to be an on-screen annotation addressing this, but it was lost when UA-cam discontinued the annotations feature years ago. From a previous comment I left: "You are absolutely correct about example 4 - it's a fascinating example of a-flutter combined with a probable Wenckebach phenomenon in the AV node, resulting in an apparently fixed 12:5 AV block. These types of very complex repeating patterns are seen on rare occasions. Although it's regularly irregular as seen from your close inspection of the EKG, on auscultation most people wouldn't be able to pick up the subtle repeating pattern and it would sound like it was irregularly irregular. (Not really sure what I was thinking when I labelled it irregularly irregular, but maybe that was it?). I've added an annotation to correct this."
Awesome, a concise logical approach to extremely convoluted branch of ECG interpretation. lovin it.
Example #9...junctional tachycardia???
Thats what I thought.
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Hello,
I'm in paramedic school currently learning about cardiology and EKG interpretation and your videos have given me a great head start towards understanding it. I do have one question though. When Example 9 came up, I went through the algorithm that was taught in my class (which is very similar to yours, except it focuses on atrial activity first) and I determined it was Junctional Tachycardia (from the narrow QRS complexes, regular rhythm of +100 beats/min, and lack of definitive P waves) as oppose to SVT or Atrial Flutter. I also learned that SVT is only indicated in a heart rate of +150 beats/min and that Atrial Flutter is characterized as having distinct flutter waves. I personally don't see any evidence of flutter waves and if there was any indication of P waves it would be in the precordial leads with a very faint morphology. I could also see in leads II, III, aVF, and V1 of what may look like a P wave buried in the QRS complex, but wouldn't that be caused by the junctional rhythm anyway?
Thank you for your time
Jonathan Souther There is no specific cutoff of heart rate for an SVT. While SVTs are usually above 150, they don't need to be. Regarding this being flutter, it would be highly unusual for the flutter waves to be more visible in V5-6 than the inferior leads or V1, but it could be an atypical flutter (i.e. reentrant circuit using an unusual pathway), which could also explain why it's relatively slow for 2:1 flutter. While the EKG is theoretically consistent with junctional tachycardia, junctional tachycardia is a very rare rhythm in adults - essentially only seen in adults with significant congenital heart disease, and can be occasionally induced in the EP lab under very controlled circumstances. If you were playing the odds, I'd say that an unusually slow AVNRT is the most likely rhythm here, but it's far from certain. What I think you are referring to as P waves buried in the QRS complex in the inferior leads is just non-specific notching of the S wave.
Thanks for getting back to me. I meant example 4 please do you think the rhythm in example 4 is regularly irregular? Thanks again
@@StrongMed
Example 3 would be so much simpler if we measured heart rates in Hz rather than BPM. Kind of ironic given that the name Hertz literally means heart.
An interesting notion - measuring HR in Hz. I agree that there may be situations in which this would make quick calculations a little easier. (though the word Hertz as the primary unit of frequency was named after Heinrich Hertz, not Herz - German for heart). Electrophysiologists actually often discuss heart rates in terms of "cycle lengths", which is the duration of time between successive QRS complexes (or P waves) in units of miliseconds. So a HR of 120 bpm might be described as "a tachycardia with 500ms cycle length".
Wow
I don't think #10 is the atrial flutter with 2:1 AV block. That's my problem because of interpretations' differences.
Excellent teaching!
Thank you Strong Medicine!
In the last example... The reason for broad qrs complex?? SVT WITH ABERRANCY... I mean in this case SVT(atrial flutter) with aberrancy( previous LBBB).... Am I right... Pls correct if I am wrong
Yes! In example 10, the patient also has a left bundle branch block.
Sir, would you know why the QRS complex in example 2 is inverted?? Thanks in advance
Isn't st segment elevated and t wave inverted in example 2
Yes, that's correct - example 2 also shows an anterior STEMI.
@@StrongMed thanks sir for your reply and clearing my doubt. I did not anticipate such an early response.
Question 7: How to think like you Sir?
Awesome thanks, in example 9 on the limb leads do the s waves have some inconsistencies that could be p waves?
I almost worship your videos!
Thank you again for the videos, Dr Eric. The videos with examples and systematic approaches to the diagnosis are the most helpful for me
example 4, the rhythm is regularly irregular thus A flutter with consistently variable AV block.
Yes, I agree, and good catch! The following is copied and pasted from another reply of mine elsewhere in the comments:
"Thanks for the comment! You are absolutely correct about example 4 - it's a fascinating example of a-flutter combined with a probable Wenckebach phenomenon in the AV node, resulting in an apparently fixed 12:5 AV block. These types of very complex repeating patterns are seen on rare occasions. Although it's regularly irregular as seen from your close inspection of the EKG, on auscultation most people wouldn't be able to pick up the subtle repeating pattern and it would sound like it was irregularly irregular. (Not really sure what I was thinking when I labelled it irregularly irregular, but maybe that was it?). I've added an annotation to correct this. [the annotations feature was removed from UA-cam several years ago]
Regarding example 5, although from afar it appears regular, if you actually measure each RR interval, there is a bit of variability. I just asked a cardiologist how she would characterize the regularity (or lack thereof) of torsades, and her response was that it's just semantics that doesn't impact the diagnosis of this specific rhythm."
@@StrongMed i did benefit a lot from this series. thank you for your efforts. i owe you.
I can't thank you enough Dr. Eric :) much gratitude!
Thank you Dr Strong :)
very nice presentation
Thought the last example was A flutter with LBBB...hack, what do I know.
But the last example *is* atrial flutter with 2:1 AV block + LBBB. I don't mention the LBBB because most viewers watch these videos out of order and may not know what a bundle branch block is yet.
Ah, I see! Thanks for making all these videos. I often come back and rewatch them.
@@StrongMed I thought I was wrong about the LBBB. I had to check the comment section to see if anyone else noticed. I'm glad I could distinguish that, thank you!
awesome
Why the last example can't be SVT?
The atrial activity is occurring with a periodicity of 300 cycles/min, which is simply too fast for rhythms other than atrial flutter. However, there is a semantic argument as to whether atrial flutter should be placed into the general category of "SVT", and probably most physicians in the US do this without thinking too much about it. Cardiologists generally consider a-flutter (and a-fib) distinct from the supraventricular tachycardias on account of differences in treatment, and the fact that flutter is relatively easy to distinguish on ECG while the other/true SVTs (e.g. AVNRT, AVRT, atrial tachycardia) are relatively hard to distinguish from one another. For this series, I take the cardiologists' viewpoint and do *not* consider a-flutter a type of SVT.
Amazing
Thanks a lot!
excellent video
Very good!
hey Eric, in the last example, is not there a R R-prime pattern in V5 lead. This together with a marginally wide QRS makes up for LBBB. Can you please clarify? :)
Good pick-up! It's not the most classic LBBB ever (e.g. the R waves in I and aVL are usually more prominent, and QRS duration is usually more prolonged). I made this a few years ago (i.e. I might be misremembering), but I probably didn't mention it because some people watch these videos out of order, and I didn't want to confuse viewers by talking too much about bundle branch blocks when they might not be familiar with them.
In that case Eric, what points would suggest that this is NOT an SVT (given the irregular relationship of P waves withe QRS complex) with abberency (LBBB)? Thanks!