Comprehensive Guide to Tachyarrhythmias: ECG Analysis and Classification

[Music] hi friends i'm dr mailanandi in this session we are going to discuss on

tachyarrhythmias so what is the objective of this session at the end of this session you will be able to find

out the abnormal rhythm given in an ecg for example i have given two ecgs to analyze the rhythm

one is given here the other one is at the end of the class so what is the definition of tachyarrhythmia it is

self-explaining arrhythmia means abnormal rhythm and taki means the heart rate is more than

100 beats per minute we use tachycardia in place of tachyarrhythmias

but the two terminologies are different we commonly use tachycardia when there is problem within the sinus node

there is increased rate in the sinus node it may be physiological or pathological whether

this rhythm is normal or abnormal we don't see any p waves and the qrs complexes they are bizarre is there any

tachycardia or not so we have to calculate the heart rate how are we going to calculate the heart

rate 300 divided by number of large boxes between two or waves

so how many lodge boxes are there one and two 300 divided by two

the rate is 150 yes this ecg shows tachyarrhythmia we are

going to analyze this ecg in a step-wise manner to find out the rhythm this image shows

normal impulse formation and conduction take arithmeos can happen if there is problem in impulse conduction

usually there will be re-entry there will be circus movement of the electrical activity around the part of

the heart for example around the trichos in atl fibrillation it may also happen if there is problem in impulse

formation for example if the subsidiary pacemakers are like for example in the atrium if

this starts firing at a rate higher than the ac node rate you come across tachyarrhythmia the

commonest cause for tachyrhythmia is reentry this is a commonest cause in day to day

practice a simple classification of tachyarrhythmia is based on the site of origin of

impulses it may be ventricular tachy arrhythmia or supraventricular tachyarrhythmia we

are more worried about ventricular tachyarrhythmias because they are associated with overall prognosis if not

recognized and treated early superanticlota key arrhythmias are further classified

as atrial tachyarrhythmia or junctional tachyarrhythmia

injunctional tachyarrhythmia the impulses start from the av node or the adjacent area but the proper way to

classify tachyarrhythmia is based upon the duration of the qrs complexes so what is the normal duration of the qrs

complex it is less than 100 milliseconds so if the qrs duration is less than 120

milliseconds we are going to say it is a narrow complex tachy arrhythmia if it is more than 120 milliseconds you are going

to say it is a white complex or broad complex tricky arrhythmia in narrow complex tachyarrhythmia the impulses

start from the atrium or from the av node and they activate the ventricles

simultaneously with a resultant normal or near normal qrs duration in white complex ducky arrhythmia the

impulses may start from the ventricles the impulses will then propagate by other meiosis

it takes longer time to activate both the ventricles with the resultant prolongation of the

qrs complexes or the impulses may start from the atrium or av node

then they will travel via an abnormal his bundle that means the patient has either or bbb

or elb bbb or there may be an accessory pathway we are going to discuss about this

accessory pathway later so whether this ecg shows narrow complex chucky arrhythmia or

broad complex tachy arrhythmia let's calculate the qrs duration in v6 this is the beginning of the

r wave and this is the end of the s wave so what's the total duration it almost occupies your large box that

means it is 200 milliseconds so it is an example of white complex stucky arrhythmia

this white complex as well as narrow complex tachycardia are further classified based on the regularity of

the qrs complexes if the qrs complexes are going to occur at regular interval we are going to say it is regular nct or

regular wct if we occur at the irregular interval we say it is irregular nct or irregular

wct so this one is a regular white complex tachyarrhythmia or irregular white complex turkey

arrhythmia so in rhythm strip we are going to assess the distance between the qrs

complexes so they occur at regular interval

so this is a regular white complex tachyarrhythmia first we are going to discuss on narrow

complex trachea rhythmia we have already subclassified this narrow complex tachyarrhythmia into two types

regular and irregular let's discuss on regular narrow complex tachycardia so what are the causes sinus

tachycardia is the commonest cause for regular narrow complex tachycardia it may be physiological or pathological

it has been dealt already the second cause being junctional tachycardia where the impulses thoughts

from the av node or the adjoining area this has been already discussed earlier so what are the other causes for regular

narrow complex tachycardia av nodal reentry tachycardia atrioventricular

re-entry tachycardia atl tachycardia and finally atl factor we're going to discuss these arithmeons

one by one this image shows all the common causes for regular narrow complex

tachyarrhythmia first we will discuss on avnrt so what is the problem or where is the problem

there is problem within the av node let's see what is it in patients who are prone to have av nrt

there will be two pathways within the av node this is a slow pathway which conducts very slowly but has a short

refractory period and this is the first pathway which conducts falsely

but it has a long refractory period that means it takes some times to conduct another impulses

normally the impulses will be conducted via the fast pathway with the resultant normal pr interval

so during the episode of avnrt what happens an atl ectopic

occurs at critical time so this ectopic enters the av node and at the upper part of the av node it

finds out that the first pathway has not yet recovered after conducting an impulse so it will not conduct an

impulse right now so the impulses will pause while the slow pathway to activate the ventricles with the resultant

widening of the pr interval in the lower part of the av node it finds out

that the fast pathway is now ready to conduct an impulse so this impulse will go retrogradely through the first

pathway to the upper part of the av node from the upper part of the av node the impulses will be conducted back to the

atrium to activate the atrium as well as via the slow pathway to

activate the ventricles this cycle goes on unless you are going to give some drugs to block the av node

here you have to see one thing the atl activity happens simultaneously with ventricular activity

so what is the implication of this one so you will not be seeing a p wave during tachycardia if the patient has a

v n r t so the p waves are often hidden within the qrs complexes so you

don't see any p waves or sometimes the atl activity happens just after the ventricular activity

and the pva will be abnormal because it is conducted from the av node to the atrium so there will be negative p wave

in lead to literary avf happening after the qrs complexes so this is known as pseudo s pattern

and there will be positive pv in lead v1 you can see this one no so this is known as sudo or dash

next we will discuss about a b or t so what is avrt it is atrioventricular re-entry tachycardia

the classical example for this being w p w syndrome wolf parkinson white syndrome in old parkinson's in white syndrome

there will be an abnormal pathway known as bundle of kent so this connects the

atrium to the ventricle and this pathway has the property to conduct the electrical

impulses so the electrical impulses will be conducted from the atrium to the

ventricles or from ventricles to the atrium normally the av node conducts the

impulses from the atrium to the ventricles the other part of the av group are electrically impermeable

so in patients with av or t the electrical impulses either enter away or the a b node that

is known as orthodomic avrt or retenter y or the bundle of skin that is known as antidramic avrt

first we will discuss on orthodomic kvrt so in orthodontic kvrt impulses from the

atrium or from the ac node enters the av node this activate the ventricles after

activating the ventricles via the bundle of kin the electrical impulses travel back to the atrium to activate it then

it enters the av node and the cycle goes on unless you are going to give some drugs to block the av node

antidramic there will be abnormal conduction via the bundle of kun to the ventricles the impulses will return to

the atrium via the his purkinje system so what are the ecg manifestations the rate is usually around 200 to 300

beats per minute in this example so that is stucky cardia you look at v1

there is some abnormality in the top of the t waves so this is caused by retrograde p wave

that is falling on the t waves so whenever you come across tachycardia and if you are not going to find out pv you

carefully look at the qrs complexes st segment on tv for any deformity the deformity may be produced by

superimposition of the p waves next we are going to discuss on ectopic

atrial tachycardia so that is atl impulses formed and this impulses will be

conducted to the atrium to activate it as well as the ventricles via the av node

as the impulses start not from the ac node but from some other part of the atl tissue there will be abnormalities in

the p wave you must be knowing that p wave should be upright in lead to lit 3 and avf if the p waves are

inverted in lead to lead 3 and avf you have to suspect ectopic atrial origin of the impulses

so commonly this ectopic or focal lateral tachycardia starts from the right lower

part of the atrium so with the resultant negative previous in lead to lead 3 avf but when you look at the rhythm strip

all the p waves are similar even though they are inverted they are similar it means the impulses start from single

focus finally we are going to discuss on atrial flutter in hl flutter the electrical activity will be moving

around the tricuspid valve annulus that is a typical atl flutter so the impulses will

activate the atrium as well as the ventricles via the av node so what are the ecg changes

so there will be regular atl activity it will be around 300 beats per minute but not all the impulses will be conducted

to the ventricles there will be block at the level of av node so the there will be

block within the av node the block may be in the pattern of 2 is to 1 3 is to 1 or 4 is to 1. if the block is fixer you

get regular narrow complex stucky arrhythmia if the block is variable sometimes

it conducts with 2s to 1 block sometimes with 4 is to 1 block you get irregular narrow complex tachyarrhythmia

to say atrial flutter there should be negative flutter waves in lead to lead 3 avfuc

so this is the negative flutter wave it resembles sawtooth waves so in lead to lit 3 avf there should be

sawtooth pattern and in v1 you see opera upright flutter

waves they resemble normal p waves so when you come across an ecg with regular narrow complex tachycardia

you're going to look for p waves if they are you are unable to find out the p waves

you have to suspect av and rt if the p wave is there now calculate the atl rate if the atl rate is greater than the

ventricular rate you suspect atl flutter or ectopic atrial tachycardia if not so

you're going to analyze the rp interval so what is the meaning of this rp interval it means

from the beginning of or to the beginning of p wave during normal sinus rhythm

this is pr interval beginning of p to the beginning of or this is p or interval

you compare this pr interval with rp interval from the beginning of or to the beginning of pv

so during normal sinus rhythm the pr interval is short compared to the rp interval

but during some arrhythmias we have discussed about av and rt the pva happens immediately after the

qrs complexes so the rp is very short compared to the pr interval so if the rp interval is less than 90

milliseconds you have to suspect av nrt so if you have discussed about regular narrow complex stack arrhythmia now we

are going to discuss on irregular narrow complex tachyarrhythmias there are only three common causes

for this one the commonest cause for irregular narrow complex arrhythmia atrial fibrillation

there is no organized atrial activity you see multiple

atrial wavelets but they don't activate the atrium as such so there is no

coordinated atl activity so there will be no p wave but if there is

no atrial contraction there will be stagnation of blood whenever there is stagnation there is

increased risk of clot formation this cloud can dislodge can enter any part of the body either the systemic circulation

or pulmonary circulation if it enters the cerebral circulation this leads to cardio embolic stroke

we have already discussed about atrial flutter if there is atrial flutter and variable block at the av node

you get irregular narrow complex tachyarrhythmia the last one being multifocal atl

tachycardia there are multiple areas of impulse formation within the atrium

but these impulses they activate the atm as well as the ventricles to say multifocal atl tachycardia at

least you have to find out three different pva morphology this is one this is two

this is third you see all the p waves they are different this multifocal lateral tachycardia is

commonly associated with obstructive rv disease like copd chronic obstructive pulmonary rv disease and pneumonia so

when you see an ecg with irregular narrow complex tachy arrhythmia look at the p wave if the p baby is absent

you're going to say this is atrial fibrillation so you don't see any p wave this is

qrs complexes t wave there is no p wave at all but sometimes you come across

ecg with the coarse baseline these are fibrillating waves but not the p waves

you should not confuse fibrillating with fibrillating waves with p waves this happens in patients with recent onset

atl fibrillation to say atrial flutter there should be flutter waves in sawtooth pattern can

lead to literary avf on multiple pva morphologies suggest multifocal atrial tachycardia

now we are going to discuss on white complex tachycardia

so what are the causes for white complex tachycardia we have already divided the white complex tachycardia into regular

and irregular wct so what are the common causes for regular wct

ventricular tachycardia this is the commonest cause or supraventricle tachyarrhythmia with evident conduction

what's the meaning of aberrant conduction there is problem

either there is right bundle branch block or left bundle branch block other may be an accessory pathway these are

the two common causes for regular wct and irregular wct may be caused by polymorphic vt

it means there are multiple foci of impulse formation within the ventricles

or atrial fibrillation with aberrant conduction you know the meaning of aberrancy

we have already discussed that this ecg shows regular white complex tachyarrhythmia

so what are the differential diagnosis either this is vt or svt with turbulent conduction can we

differentiate vt from svt by looking at the ecg yes there are so many criterias to differentiate vt from

svt the commonly used one being brugadas so if you come across an ecg with regular white complex stucky arrhythmia

look at the qrs morphology and compare it with the qrs morphology of the previous ecg that was taken during

normal sinus rhythm if both are similar you say it is svt with everyone conduction

if the previous ecg is not there you look for typical rbb or lbb pattern if it is there you're going to say svt

if both are not there then you're going to apply the brugadas algorithm

i have taken only few points of brugada's algorithm you have to read fully about the brugada's algorithm

it says you look for concordance what is the meaning of concordance you look at the

chess leads from v1 to v6 you look at all the qrs complexes

here all the qrs complexes are negative or below the baseline

so this is known as negative concordance the second example all the qrs complexes are above the baseline you're going to

call it as positive concordance uniformity you can say uniformity so if there is concordance pattern it is

diagnostic of vt if it is not there and you are going to find out any rs complexes what we are going to do

if there is rs complexes from v1 to v6 you are going to assess the distance

between the beginning of or this is the beginning of or to the nadir of s wave

so assess the distance if it is more than 100 milliseconds it is diagnostic of vt

and if there is slurring at the lowermost point of sv it is also diagnostic on vt

you have to apply all other criterias to say whether it is vt or svt so what are the

contributing factors you look for av dissociation you must be knowing the terminology

the atm the star says atrial activity so these are the atl activation and these are the

qrs complexes caused by ventricular activation there is no relationship between atl activity and ventricular

activity atm is contracting on its own and the ventricles are contracting

on the wound no relationship between atrial and ventricular activity

if it is there it is diagnostic of vt and you look for capture or fusion wheat

so what is the meaning of capture beat you compare these qrs complexes with this one

compared to this qrs complex this qrs complex is narrow and it is preceded by a p wave so

what is the meaning of capture weight it means during the episode of vt

the sinus impulse may be conducted via the av node and temporarily captures the ventricle that means the ventricle is

activated by the sinus impulse so you see pva normal pr interval and

normally looking qrs complexes it is diagnostic of vt and you look for fusion beat what is the meaning the

ventricles are activated partly by the conducted impulses from the sinus node and partly by the

ventricular ectopic so diffusion between the two so in ecg with vt

you may also find out axis which is northwest and

you assess the duration of the qrs complexes when the duration is more than 160 millisecond it

is also suggestive of vt so we are finally coming to the end so whether it is vt or svt with everyone

conduction so we are going to apply the brugadas is there any concordance

no concordance some of the complexes are positive and predominantly here you see negative

complexes but you see rs complexes from v1 to p6 so now we are going to assess

the rs interval it means from the beginning of or wave so this is the beginning i'm sorry this

is the beginning this is the beginning of the rv but then add a half sweep

so you one two three four so it is more than 100 milliseconds so it is diagnostic of vt

so when you come across an ecg like this you have to alert your team immediately probably the patient may be having

myocardial ischemia or infarct you have to recognize it and treat it promptly to sum up

so we are going to see an ecg and find out that the rhythm is abnormal so this is an abnormal rhythm we don't see any p

waves okay this is an abnormal rhythm you're going to find out the rate so how are we going to calculate the

rate here the qrs complexes occur at irregular interval or half azurely so

here you cannot use 300 divided by number of large boxes or thousand five hundred divided by number of small boxes

between the or waves so you have to calculate the number of qrs complexes in

30 large boxes and multiply it by 10 this has been discussed already so how many

qrs complexes are there approximately 14 and multiply it by 10 so the rate is 140

so this is tachy arrhythmia so first find out what is 38 then

whether the rhythm is normal or the rhythm is abnormal if that is tachy arithmeon we are going to approach in

step wise manner so you're going to see

whether this is a narrow complex turkey arrhythmia or a broad complex tachyarrhythmia

let's calculate the qrs duration it is less than two small boxes

okay so it is less than 120 so this is a regular narrow complex techie arrhythmia if it is regular narrow complex techy

arrhythmia you're going to find out whether the qrs complexes are correct regular interval or irregular interval

these qrs complexes occur at irregular interval so this is a

this is an example for irregular narrow complex trachea arrhythmia what are the differential diagnosis

only three possibilities atrial fibrillation being the commonest cause

atrial flutter with variable av block and multifocal atrial tachycardia so we are going to look for

p waves if there is irregular narrow complex stack arithmeon so in the rhythm strip we are going to

look for p waste do you see any p wave this is a qrs complex st segment on p wave no p wave qrs

complex st segment and t wave you see some

coarse baseline especially in v1 you see coarse baseline they are actually not p waves so it is

indicative of atrial fibrillation probably of recent onset so this is about

taki arithmeos next we are going to discuss on premature

ventricular complex it is self explaining there is a premature beat starting from

the ventricle and activate both the ventricles we usually call it as ventricular ectopics

how are we going to find out the winter cloud ectopics you look at all the qrs complexes

one two three four five six seven of the seven two complexes are abnormal the remaining five complexes are

normally conducted sinus impulses osmond if state by pv

under normally appearing qrs complexes so this qrs complex is broad you calculate the duration one two three so

it is more than 120 millisecond so there is a broad qrs complex and it occurred early we expect the normal sinus beat

here but this

ectopic has happened early and you look at the st segment on tv compared to the st segment and t waves

of the normally conducted sinus beat these st segment and tvs are busy

these are known as secondary st secondary st sigma and t wave changes why do you come across primary st

segment and t wave changes in patients with myocardial ischemia and look for compensatory pause what is

the meaning of it we are going to assess the distance between the sinus rhythm which happened before the

ectopic and after the ectopic this duration will be twice that of the normally conducted sinus impulse so what

you come across incomplete compensatory pawns in patients with atl ectopic

these are the few terminologies used to describe ventricular topics what is the meaning

of uniform collect topics in a rhythm strip all the qrs complexes will be

similar okay this means they have started from single focus and multifocal

vpcs in in a rhythm strip the qrs morphologies will be different it means there are multiple foci within the

ventricles and what's the meaning of by gemini it is associated with digoxin toxicity

there will be a normal sinus rhythm ectopic underpass this

goes on this is by germany and in trigeminy two normal sinus beat followed by an ectopic and pass this cycle goes

on thank you