ECG Information Flashcards
How long should be PR interval be?
.12-.2 seconds
(3-5 small squares)
How long should the QRS complex be?
0.05- 0.1 seconds
QRS complex longer than .12
Bundle branch block
Ventricular hypertrophy
Q wave should be how long?
0.03 (about 1 small square wide)
or 1/3 tall of the entire QRS complex
QT interval should be how long?
From the begining of the QRS–> end of T
0.35 seconds
A short PR interval indicates what?
- WBW dz
- Levines
- Glycogen storing dz
- HTN
- Junctional/nodal rhythms
A long PR interval can indicate?
- AV block (because this is the time it takes to get from the SA node through the AV node)
- Hyperthyroidism
During diastole, what is happening
Ventricle relaxing
Atria contracting
During systole, what is happening?
Ventricle is contracting
Atria is relaxing
Stages of cardiac cycle
- Atrial systole
- Isvolumetric ventricular contraction
- Ventricular ejection
- Isovolumetric ventricular relaxation
What stages in cardiac cyle are we in during QRS?
- Atrial systole
- Isovolumetric ventricular contraction
Why are we in isovolumetric relaxation during the last part of T wave?
Because our cells that are the 1st to depolarize are the last to repolarize
End of QRS interval begins what?
Ventricular ejection
How do we find the degree of axis?
- Find the area that the QRS wave cancels out.
- Go to the axis of deviation and find the one that is perpendicular
Movement of ST segment tells us what?
ventricular myocytes are not depolarizing at the same time and we cannot reach an isoelectric point
ST depression
subendocardial infarction
ST elecation
subepicardial or transmiral ischemia
What represeents the length of ventricular systole on ECG?
QT interval
QT interval can tell us what?
- Mycardial ischemia (T wave)
- Myocardiac injury (ST segment)
- Myocardial infarction (Q wave)
PR segment tells us what
Time to go from AV node–> ventricles
If P wave occurs after QRS?
1. SVT
2. Junctional rhythm
3. Change side of pacemaker
Why is repolarization upward deflected?
It moves away from the lead
QRS assignments
Q- first negative defletion BEFORE R
R- first upward deflection
S- negative deflection after the R
What do we use on the ECG to tell us heart rate and rhythm?
Rhythmic lead II at the bottom
When we describe an area of infarct, what part of the heart are we referring to?
LV
Injury–>
elevated ST
Infarction
Deep and wide Q, more than 1 square wide
Anginga
only an inverted T wave
How to find a STEMI
Look at all the leads except aVR.
- Look for a deep Q wave
- Look at the ST segment to tell us if acute or not. It is the first sign of an MI and returns to baseline with time.
- Look for an inverted T wave
How can we spot the difference between a anterior and posterior acute MI?
Subendocardial infarction?
Anterior acute MI- a significant Q wave and a ST elevation in V1 and V2
- Posterior acute MI would have the opposite effects because they depolarize in opposite directions
- Large R wave in V1 and V2
- ST depression
—–if only ST depression–> subendocardial infarction
-
1 AV block
Delay between the atrial and ventricular depolarization is lengthened (PR interval= >/2 seconds)
remains consistently prolonged
2 AV block
Some P waves send signals to ventricles, while smoe atrial depolariations are blocked, leacing long P waves without a QRS
2 types
Type 1–> Wenckenback
Type 2–> Morbitz
Type 1
2 AV Block
QRS looks normal
One less QRS than P wave because the PR interval lengthns but last one does not go to ventricle
Type 2 2 AV block (morbitz)
3: 1
4: 1
5: 1
How to determine what kind of block
- Look at PR interval:
is it long and stay the same length? Yes–> 1 degree
Gets longer? Yes–.> 2 degree
