12 lead EKGs and STEMI--Question

June 15, 2010

My inquiring mind needs (LOTS OF) help:

How does one know by looking at a 12 lead that the pt. is experiencing an ST

elevation MI.

Ok, I know about " ST ELEVATION " --but in what leads, aside from a simple three

lead?

Please, Gene, don't make fun of me! (LOL).

Thanks, and everyone stay safe!

June 15, 2010

Look for ST elevation in 3 contiguous leads.

Contiguous = next to each other anatomically.

Leads contiguous to each other:

II, III, AVF

V1, V2

V3, V4

I, AVL, V5, V6

And then look for ST depression in reciprocol leads. Recirpocal leads

are opposing leads:

II, III, and AVF : I, AVL

I, AVL, V3, V4, V5, V6 : II, III, and AVF

Also, V1, V2, V3, and V4 are reciprocal to the posterior site, and a

normal 12 lead will have no leads facing the site, so if you see ST

depression across those leads, (paramedics and doctors, please correct

the following if I'm wrong), I would assume it's still referred to as

a STEMI.

That being said; having the information is the simple part. Knowing

what to do with it is a bit more complicated.

Alyssa Woods, FF/NREMT-B

Sent from the itty bitty keyboard on my iPhone

On Jun 15, 2010, at 7:30 PM, Medicine Man medicineman501@...>

wrote:

> My inquiring mind needs (LOTS OF) help:

>

> How does one know by looking at a 12 lead that the pt. is

> experiencing an ST elevation MI.

> Ok, I know about " ST ELEVATION " --but in what leads, aside from a

> simple three lead?

>

> Please, Gene, don't make fun of me! (LOL).

>

> Thanks, and everyone

> stay safe!

>

June 15, 2010

Medicine Man, ST elevation can occur in a number of leads, and several

infarct imposters - like BBB, early repolarization, ventricular beats

and LVH - can produce ST elevation that mimics an MI to the untrained

eye. What leads the ST elevation appears in goes a long way toward

determining the location of the infarct. For example, Leads II, III and

AVF view the inferior wall of the left ventricle, therefore ST elevation

in those leads may herald an inferior wall MI. ST elevation in Leads

V1-V4 herald an anterior wall infarct, with V1 and V2 specifically

viewing the septum, and leads I, V5 and V6 view the lateral wall of the

left ventricle.

And all of the leads of a standard 12 lead EKG only view the LEFT

ventricle, however. For a more comprehensive view of the heart, you'll

need a 15, 18, or even 24 lead EKG.

I'll also caution you not to rely on a standard 3 or 4 lead monitor

display to evaluate ST elevation. Most monitors have artifact screening

mechanisms that reduce motion artifact by narrowing the frequency window

that the monitor " sees. " This has the unfortunate effect of not allowing

you to see most of the ST segment elevation, either.

12 lead EKG interpretation takes years to master, but infarct

recognition and localization is only a small subset of 12 lead EKG

interpretation, and one easily mastered by most medics with a little

training and practice. I'd suggest you purchase a copy of Bob Page's or

Tim Phalen's books on the subject, or better yet, take one of their

courses. They're both excellent.

Medicine Man wrote:

>

> My inquiring mind needs (LOTS OF) help:

>

> How does one know by looking at a 12 lead that the pt. is experiencing

> an ST elevation MI.

> Ok, I know about " ST ELEVATION " --but in what leads, aside from a

> simple three lead?

>

> Please, Gene, don't make fun of me! (LOL).

>

> Thanks, and everyone stay safe!

>

June 15, 2010

On Tuesday, June 15, 2010 19:52, " Grayson " Grayson902@...> said:

> 12 lead EKG interpretation takes years to master, but infarct

> recognition and localization is only a small subset of 12 lead EKG

> interpretation, and one easily mastered by most medics with a little

> training and practice.

Not to mention that even the 12-lead is only a small portion of the total

clinical picture necessary to competently diagnose a STEMI.

Rob

June 15, 2010

On Tuesday, June 15, 2010 19:52, " Grayson " Grayson902@...> said:

> 12 lead EKG interpretation takes years to master, but infarct

> recognition and localization is only a small subset of 12 lead EKG

> interpretation, and one easily mastered by most medics with a little

> training and practice.

Not to mention that even the 12-lead is only a small portion of the total

clinical picture necessary to competently diagnose a STEMI.

Rob

June 16, 2010

I NEVER make fun of anybody who wants to learn.

Here's what you must know about 12-leads. Each lead " LOOKS " at a different part

of the heart and registers its electrical activity. An ECG tells us nothing

about anything but what pathways the electrical currents are following, but we

can figure out that ischemic or DEAD tissue will conduct electricity in a

different way, so we can spot patches of dead or injured tissue if we know what

we're doing.

Now, what you're asking is quite simple. Think of each lead as a medic with a

telescope looking at a certain part of the heart. What s/he sees is just the

electrical activity of that part of the heart.

The leads look at different parts of the heart, just as if you were standing in

an elephant pen and looking at the elephant. If you're on the right side,

you'll see what the right side of the elephant looks like, but you won't see the

spear that was driven into the elephant's left side. If you're behind the

elephant, you'll see a big grey object with a tail. If you're in front, you'll

see a big grey object with a trunk and beady eyes and maybe some tusks if it's a

male.

An ECG is the same.

Leads I, aVL, V5 and V6 look at the left side of the heart.

Leads II, III, and aVF, look at the inferior part of the heart, which is most of

the left ventricle and the part that lies against the diaphragm.

Leads V1, V2, V3, and V4 look at the septum of the heard and the anterior part.

Lead aVR looks at the upper part of the right side of the heart and the right

atrium and right coronary artery.

Now, you've got to be acquainted with the arterial blood supply of the heart to

understand this. When a coronary artery is blocked, it will prevent blood from

reaching the areas of the heart that it serves. So you've got to understand the

blood flow to the myocardium before you can understand 12-lead ECGs, but it's

pretty easy after that.

ST elevations only reflect a " detour " of electrical current around ischemic

tissues. However, we know that when that happens, there is tissue that's

somehow compromised. So we read ST elevation as indicating that cardiac tissue

in the region that is read by a certain " lead " is ischemic and therefore

undergoing injury.

Some ECGs SCREAM MI. If you see extreme ST elevations in at least two

contiguous leads (that means two leads that look at similar parts of the heart)

you can bet the patient is having an MI.

If you want to learn to read ECGs, I recommend that you buy Huszar's Basic

Dysrhythmias and study it. Another one is Dubin's book, which has been the

standard for a lot of years but I don't think even approaches Huszar's in

explanation. Forget about Walraven. It's good for copying strips for exams,

but not much else.

GG

12 lead EKGs and STEMI--Question

My inquiring mind needs (LOTS OF) help:

How does one know by looking at a 12 lead that the pt. is experiencing an ST

elevation MI.

Ok, I know about " ST ELEVATION " --but in what leads, aside from a simple three

lead?

Please, Gene, don't make fun of me! (LOL).

Thanks, and everyone stay safe!

June 16, 2010

I NEVER make fun of anybody who wants to learn.

Here's what you must know about 12-leads. Each lead " LOOKS " at a different part

of the heart and registers its electrical activity. An ECG tells us nothing

about anything but what pathways the electrical currents are following, but we

can figure out that ischemic or DEAD tissue will conduct electricity in a

different way, so we can spot patches of dead or injured tissue if we know what

we're doing.

Now, what you're asking is quite simple. Think of each lead as a medic with a

telescope looking at a certain part of the heart. What s/he sees is just the

electrical activity of that part of the heart.

The leads look at different parts of the heart, just as if you were standing in

an elephant pen and looking at the elephant. If you're on the right side,

you'll see what the right side of the elephant looks like, but you won't see the

spear that was driven into the elephant's left side. If you're behind the

elephant, you'll see a big grey object with a tail. If you're in front, you'll

see a big grey object with a trunk and beady eyes and maybe some tusks if it's a

male.

An ECG is the same.

Leads I, aVL, V5 and V6 look at the left side of the heart.

Leads II, III, and aVF, look at the inferior part of the heart, which is most of

the left ventricle and the part that lies against the diaphragm.

Leads V1, V2, V3, and V4 look at the septum of the heard and the anterior part.

Lead aVR looks at the upper part of the right side of the heart and the right

atrium and right coronary artery.

Now, you've got to be acquainted with the arterial blood supply of the heart to

understand this. When a coronary artery is blocked, it will prevent blood from

reaching the areas of the heart that it serves. So you've got to understand the

blood flow to the myocardium before you can understand 12-lead ECGs, but it's

pretty easy after that.

ST elevations only reflect a " detour " of electrical current around ischemic

tissues. However, we know that when that happens, there is tissue that's

somehow compromised. So we read ST elevation as indicating that cardiac tissue

in the region that is read by a certain " lead " is ischemic and therefore

undergoing injury.

Some ECGs SCREAM MI. If you see extreme ST elevations in at least two

contiguous leads (that means two leads that look at similar parts of the heart)

you can bet the patient is having an MI.

If you want to learn to read ECGs, I recommend that you buy Huszar's Basic

Dysrhythmias and study it. Another one is Dubin's book, which has been the

standard for a lot of years but I don't think even approaches Huszar's in

explanation. Forget about Walraven. It's good for copying strips for exams,

but not much else.

GG

12 lead EKGs and STEMI--Question

My inquiring mind needs (LOTS OF) help:

How does one know by looking at a 12 lead that the pt. is experiencing an ST

elevation MI.

Ok, I know about " ST ELEVATION " --but in what leads, aside from a simple three

lead?

Please, Gene, don't make fun of me! (LOL).

Thanks, and everyone stay safe!

June 16, 2010

Hidy y'all,

I'm jist a country boy. I don't understand " contiguous " . Whut's that? And

whut's a " reciprocal? " Miss Alyssa done said that it's next to each other

anatomically, but I don't quite git it. Kin y'all 'splain this fer a country

boy who don't know nuthin 'cept how to put them electrodes on a patient fer them

paramedics? I'd fer shore preciate this.

Re: 12 lead EKGs and STEMI--Question

Look for ST elevation in 3 contiguous leads.

Contiguous = next to each other anatomically.

Leads contiguous to each other:

II, III, AVF

V1, V2

V3, V4

I, AVL, V5, V6

And then look for ST depression in reciprocol leads. Recirpocal leads

are opposing leads:

II, III, and AVF : I, AVL

I, AVL, V3, V4, V5, V6 : II, III, and AVF

Also, V1, V2, V3, and V4 are reciprocal to the posterior site, and a

normal 12 lead will have no leads facing the site, so if you see ST

depression across those leads, (paramedics and doctors, please correct

the following if I'm wrong), I would assume it's still referred to as

a STEMI.

That being said; having the information is the simple part. Knowing

what to do with it is a bit more complicated.

Alyssa Woods, FF/NREMT-B

Sent from the itty bitty keyboard on my iPhone

On Jun 15, 2010, at 7:30 PM, Medicine Man medicineman501@...>

wrote:

> My inquiring mind needs (LOTS OF) help:

>

> How does one know by looking at a 12 lead that the pt. is

> experiencing an ST elevation MI.

> Ok, I know about " ST ELEVATION " --but in what leads, aside from a

> simple three lead?

>

> Please, Gene, don't make fun of me! (LOL).

>

> Thanks, and everyone

> stay safe!

>

June 16, 2010

Hidy y'all,

I'm jist a country boy. I don't understand " contiguous " . Whut's that? And

whut's a " reciprocal? " Miss Alyssa done said that it's next to each other

anatomically, but I don't quite git it. Kin y'all 'splain this fer a country

boy who don't know nuthin 'cept how to put them electrodes on a patient fer them

paramedics? I'd fer shore preciate this.

Re: 12 lead EKGs and STEMI--Question

Look for ST elevation in 3 contiguous leads.

Contiguous = next to each other anatomically.

Leads contiguous to each other:

II, III, AVF

V1, V2

V3, V4

I, AVL, V5, V6

And then look for ST depression in reciprocol leads. Recirpocal leads

are opposing leads:

II, III, and AVF : I, AVL

I, AVL, V3, V4, V5, V6 : II, III, and AVF

Also, V1, V2, V3, and V4 are reciprocal to the posterior site, and a

normal 12 lead will have no leads facing the site, so if you see ST

depression across those leads, (paramedics and doctors, please correct

the following if I'm wrong), I would assume it's still referred to as

a STEMI.

That being said; having the information is the simple part. Knowing

what to do with it is a bit more complicated.

Alyssa Woods, FF/NREMT-B

Sent from the itty bitty keyboard on my iPhone

On Jun 15, 2010, at 7:30 PM, Medicine Man medicineman501@...>

wrote:

> My inquiring mind needs (LOTS OF) help:

>

> How does one know by looking at a 12 lead that the pt. is

> experiencing an ST elevation MI.

> Ok, I know about " ST ELEVATION " --but in what leads, aside from a

> simple three lead?

>

> Please, Gene, don't make fun of me! (LOL).

>

> Thanks, and everyone

> stay safe!

>

June 16, 2010

's right.

It takes a long time and lots of experience to become proficient in

interpretation of 12-lead ECGs. For me, it's been a 30 year journey and I'm

still not where I would like to be.

But do Tim Phalen's book, then Bob Page's, then Huszar's, then 's, if you

are serious about this.

I will post this practice PEARL.

If you have a 12-lead monitor, USE IT! It you're too lazy to do a 12-lead, then

you're too lazy to be employed.

Many paramedics have been taught that a Lead II rhythm strip is all that needs

to be done for most patients. BULLSHIT! A three-lead tracing only shows

limited parts of the heart.

If you have a 12-lead monitor, then use it. If you have 12-lead capability and

you don't use it, you're cannon fodder if you should happen to have screwed up

and you get sued. The lawyers will strip the skin from you piece by piece.

If you don't play with the toys you're given, they'll be taken away. So play

with your 12-lead. Unless you're a complete maladroit, it only takes a minute

or two to put the electrodes on to do a 12-lead.

If you're a paramedic but you were not taught to interpret 12-lead ECGs in your

initial training, sue the people who trained you. They defrauded you.

If you are one of those who had a deficient paramedic course, then buy the

books, read them, and learn the things you were not taught. You can still learn

the fundamentals, regardless of the failings of your training.