I know you would never want to miss

anything that could affect patient care

EKGs can tell you a ton about a

patient's cardiopulmonary status exactly

and you don't have to memorize anything

by the end of this series you'll be able

to tell whether your patient is having a

new heart attack an old heart attack or

something entirely different

the first step to good EKG

interpretation is to understand the

waves let's get started here we are next

to the electrical activity of the heart

let's pair this with our EKG tracing the

EKG tracing starts about 40 milliseconds

after the SA node fires this begins with

a P wave the P wave represents atrial

contraction next you get ventricular

depolarization through the QRS the QRS

represents the electrical activity

running first through the AV node then

through the interventricular septum and

finally to our ventricles this is

quickly followed by the ST segment the

ST segment represents the end of an

tricular contraction in the beginning of

repolarization and the whole thing ends

with the T wave which is the electrical

reset of the heart and it's preparation

for the next cardiac cycle whoa that's

fast let's take a closer look at each

wave all right here we have a 12-lead

EKG where should we look at our P waves

well normal P waves should be upright in

leads one two and upside-down or

inverted and lead AVR let's take a

closer look at lead to a great lead to

look at P wave morphology here we have a

normal QRS complex with a normal P wave

normal P waves should be smooth

monophasic and less than 120

milliseconds now let's look at to

abnormal P waves remember that when we

look at P waves the electrical activity

in the atria takes longer to travel

through larger atria so if we think

about a right atrial enlargement we

would expect our P wave to be taller

conversely if we think about left atrial

enlargement we would expect our P wave

to be longer

hey mark what are you looking at oh

we're just looking at some P waves yeah

looks like you're looking at some right

atrial enlargement yeah how'd you know

well you know how right atrial

enlargement is usually caused by a

problem in the lungs yeah

my favorite pulmonologist oh it says you

never sit on a pulmonary problem ha good

one it's pointy I get it maybe we should

move on from this atrial talk to the

heart of the matter let's talk about

ventricular contraction in the QRS

complex the QRS complex can look very

differently depending which lead you're

looking at in fact you don't have to

have all three components to make up the

QRS complex the Q is the initial

downward deflection this is followed by

an upright R it's always has a positive

deflection that's the thing to remember

about the R wave this is followed by a

downward deflection or the S wave now

let's take a look at how differently

they can look let's pull up another

12-lead EKG so here you can see that

their variety of QRS complexes depending

where you look so a lot of people want

to know what's the best lead to look at

the QRS complex I like to focus in on

the precordial leads in v1 through v6 so

let's pull those in and take a little

bit closer look okay in v1 and v2 you'll

see that you have a very small art wave

that's that upward deflection and then a

large deep s wave all downward

deflection afterwards then you move on

to v3 and v4 where the are wave and the

S wave are about equivalent finally in

v5 and v6 you see that it's mostly just

R wave and sometimes you don't see any Q

wave at all that's okay it's still the

QRS complex hey Katie

what's a migrate are we at progression

through your P cordials how long should

a normal QRS complex be less than 120

milliseconds or else I really start to

worry that we're seeing interventricular

conduction delay that would be like a

left bundle branch or a right bundle

branch block all right we'll talk about

how left bundle branch blocks and right

bundle branch blocks affect our QRS

later yeah

for now let's move on to the ST segment

and the T wave sure let's talk about all

the heart gets ready for its night next

cardiac cycle

say about the t-wave then you said whoa

that was fast

okay so I don't say any for some reason

in my head I was like what are you

supposed to say about the keyway but

it's nothing no because I took that over

so that we were balancing the knowledge

yeah I know you don't want to miss

something that could affect your

patients care EKGs are can tell you a

ton okay

Yura can see the electrical activity of

the heart let's tie this together with

our EKG tracing let's start with the P

with sure the P wave represents atrial

contraction

next comes the q RS the QRS represents

the electrical activity bring through

the interventricular septum and then to

the ventricles next is the ST segment

the ST segment represents the end of

ventricular contraction and the start of

repolarization and the whole thing ends

with the T wave the T wave is when the

ventricle electronically resets before

the next beat man that was fast

I think each of these waves have us more

of a story to tell I think you're right

let's start with the P wave yeah okay

what are the three things you're gonna

list the coronary blockage huh AV block

okay and just a pinch it's a scar or

should I say like whether they are

tissue you're right look image to know

if there is actually an actual inversion

versus just a scar tissue okay yeah do

you think that's better than just think

yeah I think listing the three things is

awkward yeah yeah I think maybe if you

just say like yeah whether this heart

attack yeah or or essentially in having

a heart attack right now yeah yeah so is

there a schema ongoing or did it already

happen something like that you could say

that right if you want to

is not the word ischemia okay then study

pathology maybe I don't know okay you

wanna use like a heart attack too and I

use the things that patients will use

okay you'll be able to tell even if the

heart attack were even happened and it's

old or even a new one it's actually

ongoing simple thing you could say is is

this an electrical problem or it's a

plumbing problem

yeah I like that nothing