EKG V & VI Flashcards
What are the 4 types of AV blocks?
1) 1st degree
2) 2nd degree Mobitz I (Wenckebach)
3) 2nd degree Mobitz II
4) 3rd degree
What interval is key in reading an EKG when differentiating between AV blocks?
PR interval (normal: 0.12-0.20 sec)
EKG is normal except the PR interval is prolonged, at a constant duration, in ALL beats. What type of block is this?
First-degree AV block, PRI > 0.20 sec (1 big box) in ALL beats
What type of EKG abnormality is this?
First-degree AV block
You’re looking at an EKG and the PR interval gets longer and longer until a beat completely drops off (P wave, but no QRS). What type of block is this?
Second-degree AV block: Mobitz Type I (Wenckebach)
What type of block is this: the PR interval remains constant (can be normal or long) until a beat is dropped
Second-degree AV block: Mobitz II
What type of block is more dangerous, second-degree AVB Mobitz I or Mobitz II?
Second-degree AVB Mobitz II - this often progresses into a complete block
True/False: AV blocks will always have a P wave
True, the SA node is firing, but the impulse gets blocked or delayed at the AV junction in an AV block
In this type of block, the atria and ventricles beat independently, with NO communication between the two. P-P is regular & R-R is regular
Third-degree AVB (AKA Complete heart block)
These types of blocks are caused by a delay or interruption in the transmission of impulses occurring below the bifurcation of the Bundle of His
Bundle branch blocks (RBBB or LBBB)
What leads are you looking at on an EKG when diagnosing BBBs?
V1 and V6 (looking at R-R’)
QRS complex is usually wide (>0.12 sec)
Which BBB is more dangerous, left or right?
LBBB never occurs in a healthy heart. These are concerning, especially if it’s new
What are some possible causes of a RBBB?
- Coronary artery disease
- HTN
- Acute PE
- Chronic electrical degeneration
- Can occur in a healthy heart
What are some common causes of a LBBB?
- HTN
- Cardiomyopathy
- Acute MI
- Aortic stenosis
- Extensive CAD
- Diseased electrical system
*Most often due to an organic heart disease, does NOT occur in a healthy heart
What characteristic feature will you see in the R waves in the V6 lead during a LBBB?
“Rabbit ears”
If you’re using the turn signal method of determing R vs L BBB, what direction is this BBB?
RBBB, you are looking at V1 - you click your turn signal UP to turn Right (LBBB also has the “rabbit ears” in V6)
When looking at BBB, the deflection of the QRS is going the opposite direction of the T wave. What is this called? Is it good or bad?
This is called discordance, and it’s good
The QRS deflection is going the same direction as the T wave in a BBB. What is this called? What does it suggest?
This is concordance, it may suggest ischemia or myocardial infarction
What is the Sgarbossa criteria tool used for?
It is used to identify an MI in the presence of a LBBB
_______ refers to reduced blood supply secondary to partial occlusion or spasm, heart muscle is savable.
________ refers to no blood supply due to full vessel occlusion, the heart muscle is dead.
Ischemia refers to reduced blood supply secondary to partial occlusion or spasm, heart muscle is savable.
Infarction refers to no blood supply due to full vessel occlusion, the heart muscle is dead.
What leads on an EKG correspond to the septum of the heart (septal leads)?
V1, V2
What are the anterior leads?
V2, V3, V4
What are the lateral leads?
I, avL, V5, V6 (L=lateral)
II, III, avF are what leads?
Inferior leads (F=inFerior)
A defect in the septal leads (V1, V2) indicates ischemia in what vessel?
Left anterior descending (LAD) artery
A defect seen in the anterior leads (V2, V3, V4) indicates ischemia in what vessel?
LAD
A defect seen in the lateral leads (I, avL, V5, V6) indicates ischemia in what vessel?
Circumflex branch of left coronary artery
A defect seen in the inferior leads (II, III, avF) indicates ischemia in what vessel?
Right coronary artery
ST depression and T-wave inversion seen in at least 2 anatomical leads indicates what?
Myocardial ischemia
There is a degree of ST depression that must be met to conclusively indicate myocardial ischemia:
> at least __mm in V5 or V6 (_____ leads) -or-
> at least __mm in III or avF (_____ leads)
> at least 1 mm in V5 or V6 (lateral leads) -or-
> at least 1.5 mm in III or avF (inferior leads)
T wave inversion is (normal/abnormal) in leads aVR and V1
T wave inversion is normal in leads aVR and V1
ST elevation in at least 2 anatomical leads indicates _______
Myocardial infarction
ST elevation: > 1mm in limb leads, >2mm in precordial leads (V1-V6)
______ is an MI without an elevated ST segment and is typically caused by an incomplete occlusion of an artery. The EKG may show ST depression, T wave inversion, or transient ST elevation. What will help you determine if this is an MI or not?
NSTEMI (non-ST segment elevation MI)
Labs will show elevated cardiac enzymes (i.e. troponin)
The arrows on this EKG are indicating ST elevation in leads II, III, and avF. This indicates a(n) _________ MI in the _______ ________ artery.
This indicates an inferior MI in the right coronary artery (RCA).
This EKG is showing ST elevation in the _______ leads, indicating an MI in the ______ ______ _______ artery.
This EKG is showing ST elevation in the septal leads, indicating an MI in the left anterior descending (LAD) artery.
This EKG is showing ST elevation in the _______ leads, indicating an MI in the ______ ______ _______ artery.
This EKG is showing ST elevation in the anterior leads, indicating an MI in the LAD artery.
A posterior MI presents with ST _______ in the septal and ________ precordial leads (V1-V4). This sees the MI “backwards”, to correct for this what do you do?
A posterior MI presents with ST depression in the septal and anterior precordial leads (V1-V4).
Obtain a posterior EKG to correct for this
Large R waves in V1-V3 (most commonly V2) as well as really large and sharp ST depression is indicative of what kind of MI?
Posterior MI
-ST depression seen in ischemia is more “sloping”, while posterior MI looks like sharp ST elevation just upside down
What abnormality is shown in this EKG?
Second-degree AVB, Mobitz II
What is going on in this EKG?
RBBB
-R, R’ in V1, wide QRS in V6
What’s going on in this EKG?
Second-degree AVB, Mobitz I (Wenckebach)
What’s going on in this EKG?
Inferior ischemia, to the RCA
What is most concerning on this EKG? What artery is affected?
ST elevation in leads II, III, and avF –> indicating in inferior MI in the RCA
What is going on in this EKG?
LBBB (QRS pointing down in V1, rabbit ears in V6)
What is most concerning on this EKG? What artery is affected?
ST elevation in V1 and V2 indicating a septal MI of the LAD
What’s going on in this EKG?
First-degree AV block
This def doesn’t look good. What’s going on?
Third-degree AV block, AKA Complete heart block (this rhythm oftentimes looks verrry slow)
Abnormalities in leads I, avL, V5 and V6 indicate a problem in the ________ artery.
Circumflex artery (a branch of the LCA)
What is most concerning on this EKG? What artery is affected?
ST elevation in leads I, avL, V5, & V6 –> Lateral MI from the Circumflex artery
Some MIs typically occur together based on the anatomy of the heart and its blood supply. What 2 commonly paired MIs?
Inf/Post &
Ant/Lat
