This video ( Arrhythmia (part 1) | Pathophysiology of arrhythmia | Animation | Anti-arrhythmic drugs) describes pathophysiology of normal heart, pathophysiology of arrhythmia, phases of action potential and mechanism of Action potential inside and otside the cell membrane.
Hello dear learners in this animated video of arrhythmia today we will see in detail the pathophysiology of arrhythmia different types of arrhythmia and antiarrhythmic agents in detail now let us start with the lecture so what is arrhythmia first of all so to understand arrhythmia we should know what is the pathophysiology of the normal heart so normally what
Happens the heart beats rhythmically and it depends on the cyanoatrial node that is known as pacemaker of the heart so when there is a change in this rhythm from the pacemaker there will be regulation of the rhythms and that is known as irregulation of heartbeat and this situation is known as arrhythmia and the situation is known as arrhythmia so first of all
How this heart works that we will see what happened so the impulse is generated over here this is a impulse generated by sa node it’s a pacemaker of the heart then it is start from this snore after that it is passed to the av node after that from here it will come to the turkey j fibers and lastly it will come to the ventricles so this is how the so this is how
The pacemaker controls the rhythm now we will see the faces of action potential so generally there are five phases of action potential so first one is phase zero here it’s it is known as rapid depolarization and it is due to sodium influx now the phase one the phase one is a repolarization and it is due to rapid efflux of potassium after that phase two it’s a
Plate to phase due to calcium influx after that phase three it’s a rapid depolarization phase due to potassium efflux and lastly the phase four or we can say first the phase four is the resting stage here it’s the resting state now we will see how it will work in detail by animation so firstly what happen we will see the faces of action potential by the video
Now firstly this is the stage is known as phase four is the resting phase what happened over here in this phase the sodium chloride as well as calcium is there having a higher concentration outside and potassium having higher concentration inside now there will be a phase zero so in phase zero what happened firstly the sodium channel opens so it will cause
The influx of the sodium ion there will be a rapid depolarization phase means because of the influx of sodium ion so more positive charge inside the cell compared to the outside after that l type of calcium channels open up and there will be a slow influx of the calcium ion after that l-type calcium channel opens up and there will be a slow influx of calcium
Ions after that phase one is there and in this phase sodium channel closes and it will inactivate sodium channel and what happen potassium channels open up leading to slow efflux of potassium ion and there will be a slow influx of the calcium ion so what happen it will make the inside more negative and outside more positive so here the rate of potassium efflux
Will equal to the calcium influx so ultimately it will reach us to the plateau stage over here and this is known as phase two after that calcium channel closes and there will be a rapid outward moment of potassium so here inside the more negative charge compared to the outside until the phase four re-establish after that what happened the this is the sodium
Potassium pump so the sodium potassium pump open up and here the sodium and potassium are there at the wrong side of the pump so there will be a moment of sodium as well as potassium occurs now this is how the action potential works now we will see if we want to understand the type of arrhythmia we should know the normal electrocardiogram so this is the normal
Electrocardiogram now we will see what is it the p wave the pq interval then qrs complex there will be t wave and the u now we will see what is p wave so it represent the depolarization of atria after that there will be a qrs complex it will represent the depolarization of ventricle then there will be a t wave so t will represent the repolarization of ventricle
And this pq interval it will represent the conduction through the av node or we can say bundle of his and purkinje fibers now we will see the types of arrhythmia now we will see the types of arrhythmia as per the site of origin there is a name given and there is a classification of arrhythmia so first one is atrial arrhythmia then the ventricular arrhythmia so
Atrial arrhythmia means the arrhythmia occurs in atrium then then the arrhythmia occurs in a ventricle means the site of origin as per the site of origin it is classified and third one is the sinus node arrhythmia means it is originated from the sa node the pacemaker of the heart so normally the normal heartbeat is in the range of 60 to 100 beats per minute
Now we will see first the atrial arrhythmia so it is classified in the four types in that we will see the first one is the premature atrial contraction means what there is a contraction of heart there is a contraction of heart behind the normal contraction it occurs because of the ectopic impulses then the second one is atrial peroximal trachycardia now here what
Happen there will be a increase in a atrial contraction rate it will be equal to 150 beats per minute it will be equal to 150 beats per minute so normal heart beat is equal to 60 to 100 beats per minute now the next is atrial flutter here the beating rate is 300 beats per minute then the atrial fibrillation so here the contraction of atria is there unconditionally
This type of arrhythmia occurs unconditionally this type of arrhythmia occurs there is a atrial fibrillation now we will see the ventricular arrhythmia so it will originate it from ventricle so here it will be classified into three types so first one is ventricular premature beads so it can produce these two conditions first one is ventricular tachycardia and
And second one is ventricular fibrillation so what is ventricular tachycardia so here the excessive ventricular contraction rates that effect on a cardiac output after that the ventricular fibrillation so what is it so most serious type of arrhythmia is the ventricular fibrillation here the ventricular coordination is completely loose so the cardiac output
Will be zero and death may cause in this type of arrhythmia because this type of arrhythmia is untreated now the next is sinus node arrhythmia so as i say the normal heartbeat is 60 to 100 beats per minute so it’s divided into two type occurs from the pacemaker of the heart so first is the sinus bedicardia and sinus tachycardia what is sinus predicate here
The heartbeat will be less than 60 beats per minute heartbeat will be decreases and here there will be increases in heartbeat so more than 100 beats per minute so here we can give the drugs to reduce the conduction velocity and we can say it will it will reduce to exchange the duration of cardiac action potential so now we will see the anti-arrhythmic drugs so
Anti-arrhythmic drugs it is classified in four classes first is class one sure we can say in class one the examples are the sodium channel blocker the class two is a beta blocker class 3 is a potassium channel blocker and class 4 is the calcium channel blocker as we have seen the action potential that may vary so there will be a chances of arrhythmia so we can
Give the drug at this site and there will be a sodium channel blocker beta blocker potassium channel blocker and calcium channel blocker so this is the mechanism beta agonist will affect over here in the phase 4 then class 1 drug will affect over here in the rapid depolarization obviously it’s a sodium channel blocker then class 4 will affect on phase 2 there
Will be a calcium channel blocker and class 3 it’s a class 3 will affect over here at the phase 3 class 3 is effect over here the phase 3 is the quotation channel blocker now the types of arrhythmia according to the action so here we can give the beta blocker we can say atroprine varabamil as well as dtsm are the example of beta blockers the sa node this is
The snow now here it’s a atria ventricles and accessory conducting tissues so at this site we can give this kind of drugs after that sure there is a ventricle so we can give over here the lidocaine and beta blockers and at this place av node we can give the beta blockers as well as adenosine so this is how the drug is classified according to the mechanism now
In the next video we will see the anti-arrhythmic drugs in detail thank you to your learners for watching the video
Transcribed from video
Arrhythmia (part 1) | Pathophysiology of arrhythmia | Animation | Anti-arrhythmic drugs By Chandni Chandarana