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
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).
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!
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.
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?
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!
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 RUclips 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."
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.
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.
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".
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 RUclips 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."
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.
![SVT (AVRT, AVNRT) | For DO, MD, NP, PA [Part 3]](/img/1.gif)
Absolutely fantastic. Such a high standard of teaching.
Awesome, a concise logical approach to extremely convoluted branch of ECG interpretation. lovin it.
Million thanks for the ECG quiz! You got me in the last one! :)
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
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).
Thank you again for the videos, Dr Eric. The videos with examples and systematic approaches to the diagnosis are the most helpful for me
I can't thank you enough Dr. Eric :) much gratitude!
Thank you Dr.Eric
Excellent teaching!
Thank you Strong Medicine!
Thank you Doctor Strong !
LOL that arbitrarily 99.5 % certainty joke at the end killed XD
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!
Nice work...تم
Thank you Dr Strong :)
excellent video
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!
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
Very good!
very nice presentation
Sir, would you know why the QRS complex in example 2 is inverted?? Thanks in advance
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?
Thanks a lot!
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???
awsome!
I don't think #10 is the atrial flutter with 2:1 AV block. That's my problem because of interpretations' differences.
Amazing
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!
awesome
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.
In ex.2, is there sign of stroke in v4’v5, v6? St elevation?
not my confidence being crushed at the last ECG
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 RUclips 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.
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
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?
Example #9...junctional tachycardia???
Thats what I thought.
Wow
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!
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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.
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".
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 RUclips 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."
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.
excellent video