Ventricular Tachycardia

 

SA node > AV node > Bundle of His > Purkinje fibers

SA 60 - 100

AV 40 - 60

Ventricles 20-40

Bundle of HIS 10-40

Purkinje 20-40

alright guys so yesterday we talked

about the diagnosis and evaluation of

wide complex tachycardias namely

ventricular tachycardia versus svt with

the barrency and today we're going to be

talking about management of ventricular

tachycardia because it's going to happen

very frequently when you're on the wards

or you have cardiology patients so let's

Diagnosis

just get right into it so let's say that

you identify a patient is having

ventricular tachycardia well the first

step that you want to do at this point

is to find whether this is non-sustained

ventricular tachycardia or sustained

ventricular tachycardia if it's less

than 30 seconds then it's non-sustained

v-tac and if it's greater than 30

seconds then it's sustained the reason

this is so important is because

constantly when you are having your

patients you're going to be getting

paged because patients are going to be

having five beat runs of vtec or 10 beat

runs of vtec and basically what you need

to know is that this is non-sustained

vtec and it's treated much differently

than if it's sustained monomorphic vtac

in these patients you can then classify

them as are they asymptomatic or are

they symptomatic in both cases i would

check electrolytes because a lot of

times if the patient's electrolytes are

really out of whack then it's a really

good idea to just replace those

electrolytes and make sure they're in a

good range so that the risk of them

having runs of vtac is significantly

diminished but otherwise if they're

asymptomatic you really don't have to do

anything in this case if they are

symptomatic then at this point you would

initiate a beta blocker or a calcium

channel blocker if they continue to be

refractory then you may decide to do

amiodarone and then finally if that

continues to be refractory then you may

start pursuing catheter ablation of

their vtac one side note that i want to

Side Note

mention are a couple things about pvcs

and vtac so basically anytime you have

three or more consecutive pvcs that is

what is called vtac another good number

to know is that if anybody is having

greater than 10 of their heartbeats are

as pvcs then this greatly increases the

chance that they're going to start

having some deleterious cardiac

remodeling from that and that may lead

you a little bit more towards wanting to

do something about it even if they're

asymptomatic there's also

certain rules

of malignancy that you should know about

which predicts the chance of a pvc

causing a significant run of v-tac and

this is called the rules of malignancy

and kind of the important ones to know

here is going to be frequent pvcs

multi-form pvcs so they're kind of

originating from different foci and then

also what's known as the r on t

phenomenon

which is basically when your pvcs are

kind of hitting right on the t wave of a

normal qrs complex and that has a

specifically high propensity for

generating a run of vtac alright so

that's basically it for the discussion

of non-sustained vtec most of the time

when you're going to get paged by the

nurses there's really not that much for

you to do check their electrolytes make

sure they're all replaced correctly if

they're asymptomatic don't really do

anything if they're symptomatic make

sure they're on a beta blocker or

calcium channel blocker now let's talk

about sustained monomorphic vtac and

here you're also gonna split it up into

two kind of categories so first of all

it's gonna be are they stable or are

they unstable and if they're unstable

then you're basically immediately going

to electrically cardiovert them or shock

them if the patient is awake and you can

Treatment

do a synchronized cardioversion then you

can do a hundred joules but honestly if

the patient is significantly unstable or

they're if they're pulseless then you

just want to start directly with a 200

joule shock and then you can up titrate

to like 300 joules and then up to a max

of 360 joules so that's pretty much the

easy treatment for unstable sustained

monomorphic vtac now what if the patient

is stable but they're having this

continuous sustained vtec what's our

treatment here so directly the answer is

going to be we're going to start with

antiarrhythmic therapy there's multiple

options here but the most common one

you're probably going to see is

amiodarone and the way that you do this

is a 150 milligram bolus over the first

milligram per minute rate of a drip for

the next six hours other options include

lidocaine 1 to 1.5 milligrams per

kilogram or procainamide 20 to 50

milligrams per minute so how do you

choose these i would say most people are

probably most comfortable with ordering

amiodarone and that's kind of the

default choice that most people will

have

the things with amiodarone are that it's

a little bit slower onset than the other

medications but it does have a higher

chance of actually reversing the

ventricular tachycardia and it actually

decreases the rate of recurrence of

ventricular tachycardia as well so it's

a very solid option the advantage of

lidocaine is that lidocaine generally

causes the least amount of hypotension

out of all three of these agents and

also potentially has a benefit in the

setting of mi the problem with lidocaine

is that it only fully reverses the vt

about 10 to 20 of the time so really

kind of a low rate of reversing the

ventricular tachycardia and then finally

you have procainamide which reverses the

ventricular tachycardia about 50 of the

time so pretty good rate there and also

has the benefit that even when it

doesn't

reverse the ventricular tachycardia it

actually slows the rate down which is

significantly beneficial as well so

those are some of the three different

options and some of the three different

reasons that you would choose uh them

amongst each other based on their

different side effect profiles and

different efficacies but in general i'd

say you should probably just start with

amiodaro it's the simplest and easiest

and most default one that most people

are going to do one thing to know is

that if the vt terminates during the

infusion you can actually stop the

antiarrhythmic therapy unless it starts

to have a recurrence again in which you

should initiate the infusion again and

then finally if they're refractory and

even despite your antiarrhythmic

infusion they're still staying in

sustained vtac then the next step would

actually be to shock as well and finally

one last thing to note is that there's

something called vt storm and there's

also something called incessant vt and

so vt storm is if you get somebody out

of ventricular tachycardia but they end

up having three or more recurrent

episodes within 24 hours then you call

that vt storm if you also have vt that

recurs within five minutes of

terminating the vt that's also called vt

storm as well and finally

incessant vt is basically when you have

vt that lasts for hours even though the

patient's hemodynamically stable then

you can call that incessant vt in either

of these scenarios if the patient is on

amiodarone or an antiarrhythmic already

then you should also add on a beta

blocker sometimes apparently propranolol

because apparently it's been shown to

have an increased efficacy of

terminating vt

but they should be on a beta blocker at

this point if they aren't already so

yeah that's my quick and simple way of

deciding how to treat ventricular

tachycardia number one is really to

identify is this non-sustained

ventricular tachycardia or is this

sustained ventricular tachycardia and

then from there you really decide how

you're going to treat the patient based

on their symptoms or if they're stable

or unstable so i hope that quick video

Outro

was very useful for you if you didn't

see the first video on evaluating and

diagnosing wide complex tachycardias

especially uh regarding differentiating

svt with aberrancy and vt then click up

over here for that video thanks again

for watching this video i know it was a

simple one but i think it was also a

useful one that warrants its own short

discussion i'll see you in the next

video and peace