i'm crying, literally. got incoming internal medicine exam in 2 days, found this video, really give me a hope to pass the exam with flying colours. thank you very much, ma'am.
Stumbled across this topic while doing my own extra research study. Your presentation is absolutely fantastic, and I believed you just made my next three-and-a-half-year of miserable life a little bit brighter. Cheers!
Did you understand why the fast pathway of the AVNRT (8:02) is the one with the long refractory period? Why is it faster when the AP takes more time to recover? Doesnt make sense to me honestly
Andrei Plopeanu Girl don't loose your hope! Keep on trying. Cardiology is a pain in the ass. I was crying like a little baby the day before my exam. But I assed the exam :) Don't stop trying :)
Thank You so much for the thorough explanation. I was diagnosed in 1998 with AV Nodal Reentry Tachy, had an ablation shortly thereafter to treat the condition. However, after the procedure my doc informed me that the affected area was too close to the a/v node, and he was not able to completely get all of it. So fast forward to today, I average 4 to 6 skipped beats per minute, with the occasional runs of tachy occurring. I am back on the heart meds, taking Metoprolol extended release 100mg 1x per day. I just somehow feel like this will be the bugger that gets me in the end. At least I now know what is happening inside my chest, Thank You :)
at 5:36 she said that the impulse can travel from the accessory node back to the AV node and cause a tachyarrythmia, my question is, since A/V node has a refractory period and can regulate the rate and rythm, why will the A/ V node cause tachyarrythmia, as in why will it let the impulse from accesory pathway through to begin with?
Why does the AV node have 2 pathways? What's between them? The AV node feels like the most important thing in this conduction system, with the SA node right behind it. What is the proper physical (anatomically close) structure to a healthy AV node and how is different in AVNRT?
Did you understand why the fast pathway of the AVNRT (8:02) is the one with the long refractory period? Why is it faster when the AP takes more time to recover? Doesnt make sense to me honestly
8:14 so does that mean normally impulse conduction in avn down to bundle of h n so forth is done by fast pathway n not slow ? cuz u said slow comes down hits fast which is refractory n it goes refractory itself? plz any help
Lorraine Gary what i was being taught, essentially narrow QRS means that the problem doesnt lies on the ventricular muscles. To make it simple, broad QRS should make you think of either bundle branch block or ectopic(s) that originates from the ventricle if that makes sense?
Sorry for my english... I will try to explain it... P waves represent the stimulation of atrium.. Sometimes electric signals from the reentry mechanism will travel towards to the atrium and towards to the ventricles... If this signal stimulate the atriums there will be a p signal which is going to be (-) in the II and (+) avR which means the atriums werent stimulate from sinus
+athena ky λοιπόν απ το όνομα υποθέτω εισαι Ελληνίδα και απ τις απαντήσεις σου καταλαβαινω οτι εισαι σε μεγαλύτερος έτος απο μενα, οποτε θελω να σε ρωτήσω κατι :P απ τη στιγμη που το re-entry mechanism γινεται ξανα και ξανα στο AVNRT, τοτε τι γινεται με τα νέα impulses που φτάνουν στο AV node απο το SA node ενώ ταυτόχρονα γινεται το re-entry? με συγχωρείς που τα μισά στα γράφω στα αγγλικά, αλλά σπουδάζω στα αγγλικά ιατρική και κάποιους όρους δεν τους ξερω στα ελληνικά 🙈
Thanks for the video. With an accessory pathway such as wpw or lgl conducting in the presence of afib with rvr it isn’t safe to give a nodal blocker such as adenosine, beta blocker, cc blocker, or even amio. However, procainamide is considered safe. What is it about the pharmacology of class Ia anti-dysrhythmics (thinking of the relatively flat phase 0 action potential in the av node that makes it safe and not prevent conduction in av node?
Very good lecture. The only thing I would change is that the slow and fast pathways are not really "in" the AV node. The slow pathway is between the tricuspid annulus and the coronary sinus and the fast pathway is on the other side of the coronary sinus. Otherwise, excellent presentation.
AMAZING Video THANK YOU! the only question I have regarding the AVNRT is: What do the 2 sketches on the right exactly represent in the heart? Is the straight line before the branch the AV node and the two branches coming from it the right and left ventricel?
So In AVRT, there can be two menifestation? (1) SA send impulses, but accessory tract is in refractory.So impulses go to normal AV conduction.When impulses reach to ventricles, the accessory tract finish refractory period.Then, impulses go from ventricles back to atrai before SA node produes another impulse (2) SA node produces impulses, some go through normal AV nodal pathway. And some go through accessory tract. Those who go through accessory tract reach faster as well as AV nodal conduction lates causing delta waves in ECG. 1.So what about ECG for 1st menifestation? 2. Did I understand correctly?
Is it normal for nodes to have slow and fast pathways?! In the first example, how come the slow pathway doesn't go down the tract? Why is it halted when the fast pathway is going through refractory period?
Just had my 2nd ablation, 3 days ago, for WPW. 10 years between procedures. Thought we had it beat (no pun intended). Hoping this one is a permanent fix!
+Chase Dear Hi I am thirteen, and last year in November l had my first keyhole ablation, I haven't had any episodes so far and I used to have strange episodes, at least, every two months I was wondering how long it took for your symptoms to come back, in case mine do, because I really don't want to take the meds for it, and I do not want to do nothing as they said as one of the options for me. So I took the option for the surgery because I didn't want it to define me for the rest of my life. You know how people are... "Oh, you came first place in that race, But don't you have that thing wrong with your heart? You didn't feel faint as you crossed the finish line?" I'm sure you know what I mean by those dumb people who assume everything... But yeah my surgeon said after a year they could take out my implant that tracks my heart (reveal device). So I was wondering if it took over a year or under to come back in case mine does (fingers crossed it doesn't) :) .
3rd question, since the reentry phenomenon is going to revolve around the AV node and the accessory pathway in a vicious cycle manner, there will be new electrical signals coming from above (SA node/atrial pacemaker cells) too right? wouldn't that cancel off the reentry mechanism and lead to a normal anterograde conduction again, if that's the case, how can it still be said "the reentry circuit phenomenon takes place over and over and over again".. because it doesnt..??
The normal sinus rythm (SA node signal) will be blocked due to the refractory period of the reentrant circuit. And you are correct, the sinus rythm might stop the AVRT if timed precisely.
Also a question, is this something one is born with? Or can this be caused later on in life? I never had any problems until I abused a cathinone called 3mmc for over a year. After a few ECG's my doc told me it's was AVNRT. I just wonder if I caused this entirely by the substance abuse or if I only 'triggered' it.
Because the accessory (extra) pathway shouldn't be there in normal anatomy, the AV node is at the "gate" but it cannot stop electrical activity from crawling through a hole in the fence 100 yards away. (I think that makes sense)
Thank you, excellent video. My only comment is that the normal QRS width is .08-.12ms, this means that in order for it to be narrow complex the parameter should be
Question: 1.) In AVRT (WPW syndrome), since electrical signals are going to inevitably travel through both the AV node and the accessory pathway, does that mean the person will have a relatively higher resting heart rate even without a premature impulse? (owing to the lack of mechanism that slows down the signals in the accessory pathway) 2.) In 5:12 you mentioned that IF there was a premature beat, it would eventually form a reentry circuit by the signal that undergoes the AV node back up to the accessory tract at the time its refractory period is over , so my question is what if there was a premature beat that travels to the accessory pathway that wasn't in refractory period in the first place? Now does it differ from normal condition without a premature beat? and what determines the refractory period of this accessory pathway? khanacademymedicine or Anyone kind enough to enlighten me please? Thanks alot in advance!
1. The resting heart rate without a premature beat depends on the SinoAtrial node rate. 2. The premature beat will travel to the ventricle and it will beat prematurely, thus the delta wave appears.
Neither. Though P-waves are absent in most all SVT's, Sinus-Tach presents as a perfectly normal sinus rhythm, simply with an elevated heart-rate over 100 BPM.
wow... leaving Thursday morning for mapping study plus or minus ablation with possible cryoballon... my hearts insane... I hope it works. thank you for this video!! would avrt or avnrt cause 17 pauses in 48 hours with the longest being 8.7 seconds?
yes it does. you may find inverted P waves after the R waves in the QRS complexes of AVNRTs (the R comes down and goes just below the baseline like a little hook, before returning to the baseline). This represents the retrograde depolarisation of the atrium from the AV node.
Best video on the internet regarding this topic. Very few people can clearly and adequately explain it. Amazing job! Thank you!
take THİS: th-cam.com/video/yLI4yj1TZhc/w-d-xo.html
Agreed!!
Totally agree 👍🏽
i'm crying, literally. got incoming internal medicine exam in 2 days, found this video, really give me a hope to pass the exam with flying colours. thank you very much, ma'am.
Hahaha samalah 😭
I spent so much time trying to find a good explanation on TH-cam, this was by far the best and most concise. Thank you so much!!
ER nurse here, been on the floor for 3 years and this is hands down the best video I've found and keep coming back to for refreshers
Stumbled across this topic while doing my own extra research study. Your presentation is absolutely fantastic, and I believed you just made my next three-and-a-half-year of miserable life a little bit brighter. Cheers!
THIS VIDEO ALONE SHOULD REPLACE ALL MY ARRHYTMIA LECTURES, I ADORE YOU
Did you understand why the fast pathway of the AVNRT (8:02) is the one with the long refractory period? Why is it faster when the AP takes more time to recover? Doesnt make sense to me honestly
This is the best video I could find on this difficult topic!
I'm not a medstudent, I'm just here because it seems I suffer from this. Thanks for the video, it is nice to get a better insight into the condition
Everyone: trying to study for exams
Me: trying to make sense of what's wrong with my heart
Can you explain your symptoms
Thank you for explaining what’s going on with my heart so clearly 💕👍🏽
much more clear than my professor explained in the class. thanks
Ok if i pass my cardiology exams i will own it to you. really
+athena ky Have mine next tuesday...this is the first video that makes things clear...started to loose my hope
Andrei Plopeanu Girl don't loose your hope! Keep on trying. Cardiology is a pain in the ass. I was crying like a little baby the day before my exam. But I assed the exam :) Don't stop trying :)
Andrei Plopeanu ce specialitate ti-ai ales la rezi? 😅
Holy shit what a video.
Been trying to learn this for the last year.
You have one very happy Paramedic student.
Thankyou.
This is wonderful. I gotta give a seminar about this in about 9 hours and now I know how to do it well. Thanks a bunch.
Best explanation i ever found. Satisfied much.
Thank You so much for the thorough explanation. I was diagnosed in 1998 with AV Nodal Reentry Tachy, had an ablation shortly thereafter to treat the condition. However, after the procedure my doc informed me that the affected area was too close to the a/v node, and he was not able to completely get all of it. So fast forward to today, I average 4 to 6 skipped beats per minute, with the occasional runs of tachy occurring. I am back on the heart meds, taking Metoprolol extended release 100mg 1x per day. I just somehow feel like this will be the bugger that gets me in the end. At least I now know what is happening inside my chest, Thank You :)
I thought i could never understand this.. bestestestestet explination.. thank you soooo much❤
This is the best video I could find on this topic, Thank you so much
Im a 5stage pharmacist from Iraq thanks you alot❤
I have watched many videos its my favourite video of all time.
Thank you
at 5:36 she said that the impulse can travel from the accessory node back to the AV node and cause a tachyarrythmia, my question is, since A/V node has a refractory period and can regulate the rate and rythm, why will the A/ V node cause tachyarrythmia, as in why will it let the impulse from accesory pathway through to begin with?
Best video so far i found on this topic
First time in my life understanding the difference
Why does the AV node have 2 pathways? What's between them? The AV node feels like the most important thing in this conduction system, with the SA node right behind it. What is the proper physical (anatomically close) structure to a healthy AV node and how is different in AVNRT?
8:27 Yep, that is perfection! 🎉
just amazing, I wouldn't have understood this topic without your video!
Did you understand why the fast pathway of the AVNRT (8:02) is the one with the long refractory period? Why is it faster when the AP takes more time to recover? Doesnt make sense to me honestly
It's pretty good. The vdo make me easy to learn about AVNRT and AVRT. Thank you!,!!
Really great job.
You made it look really easy.
I just have a little question here.
What is the significance of having a slow pathway & fast pathway?
Smn Commented theres only one pathway physiologically but in congenital defect, theres 2
This is 100000 times easier than I thought. Most people do a poor job explaining it (or perhaps they do not understand it themselves)
Thank you for creating this!! :)
Simple but excellent explanation...👍
Thank you so much for this wonderful explanation 😊
8:14 so does that mean normally impulse conduction in avn down to bundle of h n so forth is done by fast pathway n not slow ? cuz u said slow comes down hits fast which is refractory n it goes refractory itself? plz any help
Awesome 👍 explanation. Good work👏🏼👏🏼👏🏼
My lecturer's slide on this topic is so annoying and confusing. Thanks so much for making this very clear
The video says that a supraventricular tachycardia involves a narrow QRS
Lorraine Gary what i was being taught, essentially narrow QRS means that the problem doesnt lies on the ventricular muscles. To make it simple, broad QRS should make you think of either bundle branch block or ectopic(s) that originates from the ventricle if that makes sense?
Are the P waves absent in both AVRT and AVNRT? Please explain the mechanism for why the P waves are absent in either.
Sorry for my english... I will try to explain it... P waves represent the stimulation of atrium.. Sometimes electric signals from the reentry mechanism will travel towards to the atrium and towards to the ventricles... If this signal stimulate the atriums there will be a p signal which is going to be (-) in the II and (+) avR which means the atriums werent stimulate from sinus
+Doc there is still a p waves, but they are being hidden by the overwhelming impulse in SVT
+athena ky λοιπόν απ το όνομα υποθέτω εισαι Ελληνίδα και απ τις απαντήσεις σου καταλαβαινω οτι εισαι σε μεγαλύτερος έτος απο μενα, οποτε θελω να σε ρωτήσω κατι :P απ τη στιγμη που το re-entry mechanism γινεται ξανα και ξανα στο AVNRT, τοτε τι γινεται με τα νέα impulses που φτάνουν στο AV node απο το SA node ενώ ταυτόχρονα γινεται το re-entry? με συγχωρείς που τα μισά στα γράφω στα αγγλικά, αλλά σπουδάζω στα αγγλικά ιατρική και κάποιους όρους δεν τους ξερω στα ελληνικά 🙈
such an amazing way to explain svt
very well explained 👍
Thanks for the video. With an accessory pathway such as wpw or lgl conducting in the presence of afib with rvr it isn’t safe to give a nodal blocker such as adenosine, beta blocker, cc blocker, or even amio. However, procainamide is considered safe. What is it about the pharmacology of class Ia anti-dysrhythmics (thinking of the relatively flat phase 0 action potential in the av node that makes it safe and not prevent conduction in av node?
wow! you explained it amazingly well...thanks a lot!!
wow !!!! now , I understand this concept much better !!!!! thank you !!!!!!!!!!!!
Very good lecture. The only thing I would change is that the slow and fast pathways are not really "in" the AV node. The slow pathway is between the tricuspid annulus and the coronary sinus and the fast pathway is on the other side of the coronary sinus. Otherwise, excellent presentation.
more specifically it is in the triangle of coch...tendon todaro area. but YEAH!
AMAZING Video THANK YOU! the only question I have regarding the AVNRT is: What do the 2 sketches on the right exactly represent in the heart? Is the straight line before the branch the AV node and the two branches coming from it the right and left ventricel?
Just amazing. Thank you.
Much helpful video.. gud job👌👌
So In AVRT, there can be two menifestation?
(1) SA send impulses, but accessory tract is in refractory.So impulses go to normal AV conduction.When impulses reach to ventricles, the accessory tract finish refractory period.Then, impulses go from ventricles back to atrai before SA node produes another impulse
(2) SA node produces impulses, some go through normal AV nodal pathway. And some go through accessory tract. Those who go through accessory tract reach faster as well as AV nodal conduction lates causing delta waves in ECG.
1.So what about ECG for 1st menifestation?
2. Did I understand correctly?
Thanks a lot! Crisp explanation
In WPW why would the accessory pathway be in a refractory period while the normal pathway is not ?!
wow just wow ...thank you
Is it normal for nodes to have slow and fast pathways?! In the first example, how come the slow pathway doesn't go down the tract? Why is it halted when the fast pathway is going through refractory period?
Excellent explanation tq so much
You did an awesome job!
Just wish u talked alittle more about other accessory pathways.
Just had my 2nd ablation, 3 days ago, for WPW. 10 years between procedures. Thought we had it beat (no pun intended). Hoping this one is a permanent fix!
Chase Dear All the best mate! Hopefully have it covered now!
+Chase Dear
Hi I am thirteen, and last year in November l had my first keyhole ablation, I haven't had any episodes so far and I used to have strange episodes, at least, every two months I was wondering how long it took for your symptoms to come back, in case mine do, because I really don't want to take the meds for it, and I do not want to do nothing as they said as one of the options for me. So I took the option for the surgery because I didn't want it to define me for the rest of my life. You know how people are... "Oh, you came first place in that race, But don't you have that thing wrong with your heart? You didn't feel faint as you crossed the finish line?" I'm sure you know what I mean by those dumb people who assume everything... But yeah my surgeon said after a year they could take out my implant that tracks my heart (reveal device). So I was wondering if it took over a year or under to come back in case mine does (fingers crossed it doesn't) :) .
@@imogenmcintyre2339 how have you been since your ablation?
Thank you so much!! I finally understood it.
super helpful! thank you!
3rd question, since the reentry phenomenon is going to revolve around the AV node and the accessory pathway in a vicious cycle manner, there will be new electrical signals coming from above (SA node/atrial pacemaker cells) too right? wouldn't that cancel off the reentry mechanism and lead to a normal anterograde conduction again, if that's the case, how can it still be said "the reentry circuit phenomenon takes place over and over and over again".. because it doesnt..??
The normal sinus rythm (SA node signal) will be blocked due to the refractory period of the reentrant circuit. And you are correct, the sinus rythm might stop the AVRT if timed precisely.
Wonderful job ... great video...
Really very well explained! Thankyou
Can AVNRT re-enter back to atria as it loops around AV,what is the atrial rate/rhythm if ventricular was around 150 in that example,thank you..
Also a question, is this something one is born with? Or can this be caused later on in life? I never had any problems until I abused a cathinone called 3mmc for over a year. After a few ECG's my doc told me it's was AVNRT. I just wonder if I caused this entirely by the substance abuse or if I only 'triggered' it.
Wow I didn't know that the normal AV node has 2 pathways :-o none of my books mentions it :P thanks!
The normal AV node has only one pathway, physiologically. The presence of two pathways is a congenital defekt.
thanks a lot for a great explanation
this made it so clear. THANK YOU
Thank for the video! Why does the AV node not work as "the gate keeper" for the conduction from the accessory pathway in AVRT?
Because the accessory (extra) pathway shouldn't be there in normal anatomy, the AV node is at the "gate" but it cannot stop electrical activity from crawling through a hole in the fence 100 yards away. (I think that makes sense)
Thank you 🙏🏾🙏🏾🙏🏾
what happends to the P wave in SVT in AVRNT ???
This was so helpful, thank you so much!!
as below. Extreeeeemely well presented!
Thank you, excellent video. My only comment is that the normal QRS width is .08-.12ms, this means that in order for it to be narrow complex the parameter should be
Question:
1.) In AVRT (WPW syndrome), since electrical signals are going to inevitably travel through both the AV node and the accessory pathway, does that mean the person will have a relatively higher resting heart rate even without a premature impulse? (owing to the lack of mechanism that slows down the signals in the accessory pathway)
2.) In 5:12 you mentioned that IF there was a premature beat, it would eventually form a reentry circuit by the signal that undergoes the AV node back up to the accessory tract at the time its refractory period is over , so my question is what if there was a premature beat that travels to the accessory pathway that wasn't in refractory period in the first place? Now does it differ from normal condition without a premature beat? and what determines the refractory period of this accessory pathway? khanacademymedicine or Anyone kind enough to enlighten me please? Thanks alot in advance!
1. The resting heart rate without a premature beat depends on the SinoAtrial node rate.
2. The premature beat will travel to the ventricle and it will beat prematurely, thus the delta wave appears.
For the first time in 2 years I finally understand the way AVNRT works, all I knew before this is that it sucks haha.
What is the difference between Sinus Tachycardia vs SVT? The absence of the Pwave or the combining of the P wave with the T wave??
Neither. Though P-waves are absent in most all SVT's, Sinus-Tach presents as a perfectly normal sinus rhythm, simply with an elevated heart-rate over 100 BPM.
Sinus-Tach is benign in a structurally healthy heart, but may be very uncomfortable, and anxiety inducing requiring treatment with anti-arrhythmatics.
Sinus tachycardia is one type of the SVTs. So SVT is a category and not a certain arrhythmia
Mhd Awada
Yes but in an emergency medicine setting paroxysmal SVT generally refers to AVNRT or AVRT (though an EP study is required to confirm).
This video was really great.helped me to understand this difficult topic could i know the doctors name?
thank you for this video
Thank you so much! You saved me.
maam, avnrt this one refer to slow-fast right? what abt fast-slow and slow-slow?
interesting, the refectory period is basically the same thing as a capacitor charging and discharging.
WOW now that you put it that way ...... that is so right
god, this is so clear. thank you
wow... leaving Thursday morning for mapping study plus or minus ablation with possible cryoballon... my hearts insane... I hope it works. thank you for this video!! would avrt or avnrt cause 17 pauses in 48 hours with the longest being 8.7 seconds?
Thank you so so much!
Great video! Can you tell us what software you've used to create this video?
AMAZING video, Thank you very much!
What is the origin for the abnormal path in the Avnrt?
that was very good thanks
Thankyou!! Best video
So helpful thank you
Love the explaination ty
Thank you
so good thank you from an intern!
But does the reentrant circuit send signals upward to the atria ?
yes it does. you may find inverted P waves after the R waves in the QRS complexes of AVNRTs (the R comes down and goes just below the baseline like a little hook, before returning to the baseline). This represents the retrograde depolarisation of the atrium from the AV node.
Very useful, thank you
great video!
Blanda Grove
This is amazing. Thank you so much!
Amazing from Italy
Compliments!
beautiful! thanks
Thanks a lot !!! Really helpful!!!
why does the slow one even exist if the fast has a slow RP anyway... the slow is there for what ?
fast pathway has a LONGER refractory period and the slow pathway is a SHORTER refractory period
in a normal heart there's only one. Having two is a congenital heart defect.
This is abnormal .. it's not there in the normal hearts