Strip Tease 3

[chbare]

A few considerations:

1) You will have a difficult time definitively identifying ST segment elevation in the presence of bundle branch blocks. Definitively calling this a STEMI may be difficult. If these changes are new, you would have more information to base your decision. If this ECG is unchanged from a prior XII lead, you are going to have difficulty making any conclusions on ECG criteria alone.

2) In addition to a right bundle branch block, I can identify pathologic left axis deviation.

3) In addition to pathological left axis deviation, I can identify a bifascicular block.

So, we have additional information. We can research the causes of these findings and possibly correlate to our patient's clinical presentation. Without knowing the history, having an old ECG, and knowing the patient's signs and symptoms, we are just shooting in the dark at possibilities.

These could be new changes or changes from years ago.

Take care,

chbare.

[FL_Medic]

maybe my eyes are tired from the shift but that appears to be a paced rhythm thus nothing can be said about ST elevations

I think maybe you should elaborate.

[FL_Medic]

A few considerations:

1) You will have a difficult time definitively identifying ST segment elevation in the presence of bundle branch blocks. Definitively calling this a STEMI may be difficult. If these changes are new, you would have more information to base your decision. If this ECG is unchanged from a prior XII lead, you are going to have difficulty making any conclusions on ECG criteria alone.

2) In addition to a right bundle branch block, I can identify pathologic left axis deviation.

3) In addition to pathological left axis deviation, I can identify a bifascicular block.

So, we have additional information. We can research the causes of these findings and possibly correlate to our patient's clinical presentation. Without knowing the history, having an old ECG, and knowing the patient's signs and symptoms, we are just shooting in the dark at possibilities.

These could be new changes or changes from years ago.

Take care,

chbare.

Well wht might cause changes like this?

[Jeepluv77]

Okay, I feel dumb having to ask this, but what signifies a bundle branch block(all I have been told in class is that it's a "rabbit ear" on the qrs which I'm not seeing here in any lead) or left axis deviation(never even heard of this before)? I don't a problem with doing my own research, but haven't found anything that I can really make heads or tails of while being sure that it's also reliable information. Any links you might have would be greatly appreciated. Also, if you know of any books that would be worth the investment. It'll be 2 more semesters before we get into 12 lead in school but I'd like to learn it beforehand.

[akroeze]

Okay, I feel dumb having to ask this, but what signifies a bundle branch block(all I have been told in class is that it's a "rabbit ear" on the qrs which I'm not seeing here in any lead) or left axis deviation(never even heard of this before)? I don't a problem with doing my own research, but haven't found anything that I can really make heads or tails of while being sure that it's also reliable information. Any links you might have would be greatly appreciated. Also, if you know of any books that would be worth the investment. It'll be 2 more semesters before we get into 12 lead in school but I'd like to learn it beforehand.

Highly highly recommend this:

http://www.amazon.ca/12-Lead-ECG-Art-Inter...8675&sr=8-1

and for rhythm interpretation:

http://www.amazon.ca/Arrhythmia-Recognitio...8675&sr=8-1

[FireMedic65]

Highly highly recommend this:

http://www.amazon.ca/12-Lead-ECG-Art-Inter...8675&sr=8-1

and for rhythm interpretation:

http://www.amazon.ca/Arrhythmia-Recognitio...8675&sr=8-1

Those books come highly recommended by many people. I have not yet had the chance to read over the 12 lead yet, but it is on my list of things to do.

Here is a direct link to their site to see what else they have to offer. Lots of other free info on there too.

http://www.12leadecg.com

This is also another amazing book to learn EKG

Edited April 18, 2009 by FireEMT177959

[chbare]

Do not listen to people who tell you rabbit ears is a definitive finding for right bundle branch block. The ECG in this scenario proves you can have RBBB without the characteristic rabbit ears finding (AKA RSR Prime).

A bundle branch block is simply a delay or block in conduction through the bundle branch network of the cardiac conduction system. If you recall your A&P class, the conduction system essentially diverges into to bundle branches below the AV note.

If you think about bundle branch blocks, you essentially have delayed ventricular conduction as the wave of depolarization has to take alternative routes through the heart. This is manifested as a widened QRS complex. Generally, a QRS wider than 0.12 seconds (3 small boxes) indicates BBB.

Many methods exist to differentiate a RBBB for LBBB. I typically utilize what is called the turn signal criteria. If you look at V1, find the J point at the ST segment and draw a line back through the QRS. If you note a positive wave, you have a RBBB. Hence, you are turning right and your turn signal know would be pulled up. A LBBB will have negative deflection. Look at V1 in this ECG and you should be able to easily identify the upward deflection signifying RBBB.

In addition, I talked about a bifascicular block. You see, the left bundle branch actually splits into two fascicles. The left anterior fascicle and the left posterior fascicle. Named for their respective locations. These guys are tricky to spot when blocked, because you may not develop significant QRS changes, so typically, you will have axis changes with fascicular blocks. We will talk about axis in a bit. The exception being, the presence of a LBBB. If you identify a LBBB, then both of the fascicles are blocked. People talk about hemiblocks. This means only one of the left fascicles are present. However, always remember a hemiblock cannot occur with a LBBB because both fascicles are already blocked.

When I spot a RBBB, I follow this flow guideline to identify a block of one of the left fascicles:

-Is RBBB present? In this case, yes. If a RBBB is not present you cannot have a bifascicular block, because the definition of a bifascicular block is a RBBB and a block of one of the two fascicles. (Hence, bifascicular or a blockage on the right and left side, with one remaining fascicle.)

-Is lead I negative? In this case no; however, if the answer was yes, you have a bifascicular block.

-If lead one is positive, are leads II & III negative? In this case, yes, therefore we have a bifascicular block.

Why is this stuff important? Obviously, many people argue against advanced education and for skills without the background. However, think about somebody with a bifascicular block? What would occur if they loose the last remaining fascicle? What interventions should you anticipate looking at this ECG?

I will address axis in a second post, as this one is already quite long.

Take care,

chbare.

[FireMedic65]

Do not listen to people who tell you rabbit ears is a definitive finding for right bundle branch block. The ECG in this scenario proves you can have RBBB without the characteristic rabbit ears finding (AKA RSR Prime).

A bundle branch block is simply a delay or block in conduction through the bundle branch network of the cardiac conduction system. If you recall your A&P class, the conduction system essentially diverges into to bundle branches below the AV note.

If you think about bundle branch blocks, you essentially have delayed ventricular conduction as the wave of depolarization has to take alternative routes through the heart. This is manifested as a widened QRS complex. Generally, a QRS wider than 0.12 seconds (3 small boxes) indicates BBB.

Many methods exist to differentiate a RBBB for LBBB. I typically utilize what is called the turn signal criteria. If you look at V1, find the J point at the ST segment and draw a line back through the QRS. If you note a positive wave, you have a RBBB. Hence, you are turning right and your turn signal know would be pulled up. A LBBB will have negative deflection. Look at V1 in this ECG and you should be able to easily identify the upward deflection signifying RBBB.

In addition, I talked about a bifascicular block. You see, the left bundle branch actually splits into two fascicles. The left anterior fascicle and the left posterior fascicle. Named for their respective locations. These guys are tricky to spot when blocked, because you may not develop significant QRS changes, so typically, you will have axis changes with fascicular blocks. We will talk about axis in a bit. The exception being, the presence of a LBBB. If you identify a LBBB, then both of the fascicles are blocked. People talk about hemiblocks. This means only one of the left fascicles are present. However, always remember a hemiblock cannot occur with a LBBB because both fascicles are already blocked.

When I spot a RBBB, I follow this flow guideline to identify a block of one of the left fascicles:

-Is RBBB present? In this case, yes. If a RBBB is not present you cannot have a bifascicular block, because the definition of a bifascicular block is a RBBB and a block of one of the two fascicles. (Hence, bifascicular or a blockage on the right and left side, with one remaining fascicle.)

-Is lead I negative? In this case no; however, if the answer was yes, you have a bifascicular block.

-If lead one is positive, are leads II & III negative? In this case, yes, therefore we have a bifascicular block.

Why is this stuff important? Obviously, many people argue against advanced education and for skills without the background. However, think about somebody with a bifascicular block? What would occur if they loose the last remaining fascicle? What interventions should you anticipate looking at this ECG?

I will address axis in a second post, as this one is already quite long.

Take care,

chbare.

Great info, glad someone took the time to explain rather than just say to go read a book. More people need to be helpful like you.

[chbare]

This actually explains axis with the needed pictures and diagrams:

http://www.nursce.com/x_courses/1071/1071.htm

Axis is essentially, the average direction all of the electrical activity in our heart moves. (measured in degrees)

Deviate significantly from a normal axis, and you have electrical vectors moving left or right. Many causes of axis deviation such as MI, BBB, COPD, old age, normal physiological variant, and many other causes.

Look at the diagrams and numbers for normal, LAD, RAD, and the extremes such as right shoulder and pathological deviation.

The limb lead diagrams for assessing are helpful. In addition, you can always look at the QRS axis on top of the XII lead and not the number. Then compare that number to the norms and find axis.

Take care,

chbare.

[Jeepluv77]

Thank you all so much for this info. I can't wait to get those books, akzroeze. Thank goodness I have a birthday coming up because they are not cheap! And, like Aaron said, thank you chbare for taking the time to explain it. I might be stopping at emt-i for awhile(still not sure) but I don't think that should mean my learning stops in August when I test out. Even though I won't "officially" be able to read 12-lead on rescue, I will be able to as an in-hospital tech. Either way, it will definitely help my patients if I have a better understanding of what's going on with them. I'm going to check on protocols to and see if I can take 12 lead early as part of my emt-i but I doubt it because I think it's out of our scope of practice. Hence the can't "officially" read it and may not be able to fully treat it, but at least I can anticipate problems and hopefully have some idea of what I'm up against during transport.

Edited April 18, 2009 by Jeepluv77