BB Blocks Flashcards
Explain the electrical impulse and why it is deflected a certain way on the EKG?
If it travels towards the electrical impulse it is a positive deflection and if it travels away from the electrical impulse it is negative.
In what direction is the septum depolarized, which epicardium is depolarize first and why, and in what direction is the LV wall depolarized?
L to Right. Right epicardium is first because it is thinner. LV wall is depolarized apex to base.
What is the intrinsic deflection referring to?
Time it takes from the beginning of the QRS complex to the peak of the R wave. It is measuring the time it takes to reach the epicardium.
What is the measure time for the impulse to reach the epicardium on V1 and V6?
.02 and .04 respectively
So keeping all this in mind, what does it mean if it is taking longer to start the downward spike of the R wave?
It’s taking longer to get to the epicardium.
What are two causes of a longer ID?
BBB or Hypertrophy/dilation.
1 big time common feature of BBB that is diagnostic in its own right? What does it represent?
Widened QRS greater than 0.12 seconds. It represents two QRS complexes from each ventricle superimposed on one another. The one ventricle on time and the other delayed.
What is an easy way to see BBB on the EKG?
Greater than 3 small squares.
Explain the process of diagnosing BBB via EKG?
First check to see if there is a wide QRS. Then look at V1 and V2 and V5 and V6. V1 and V2 look at the right ventricle, so if you have RR looking at V1 and 2, you have RBBB. If you look at V5 and 6 and see RR, you are looking at a LBBB.
4 common causes of LBBB?
HTN, ischemia, AS, cardiomyopathy
What direction is the T wave normally in BBB?
Opposite of the QRS
What happens when the T wave is in the same direction of the QRS in BBB?
It is called primary T wave change and is usually due to ischemia
Under normal conditions, which side of the septum is activated first and how much quicker is it?
Left side is activated .01 seconds earlier than right.
Explain what the RR can sometimes look like in V5 or V6 with a left BBB?
It can be more of a flattened peak with two tiny points.
