EKG- How to Read Flashcards
leads I, II and III … what orientation in space do they “see”?
Lead I: RA (-) to LA (+) (Right Left, or lateral)
Lead II: RA (-) to LL (+) (Superior Inferior)
Lead III: LA (-) to LL (+) (Superior Inferior)
3 augmented unipolar limb leads: what do they “see” ?
Lead aVR: RA (+) to [LA & LL] (-) (Rightward)
Lead aVL: LA (+) to [RA & LL] (-) (Leftward)
Lead aVF: LL (+) to [RA & LA] (-) (Inferior)
unipolar chest leads: what do they “see” ?
Leads V1, V2, V3: (Posterior Anterior)
Leads V4, V5, V6:(Right Left, or lateral)
what is the sequence of activation of the ventricles?
- septum
- left ventricle
- right ventricle
6 things that EKG assess for?
Rate of heart Rhythm of heart Axis of ventricle and atria Intervals between waves normal Hypertrophy Infarction
rate of SA node, Atria, AV junction, Ventricles … why do we care about the rate of the areas other than SA node?
SA node: 60-100 bpm
atria: 60-80
AV node: 40-60
Ventricles: 20-40 Automaticity Foci take over if SA node fails- these are places in the conducting system that can take over the pacing responsibility
in what situation would AV node pick up the pacemaking responsibility over the SA node?
- The SA node and atrial foci fail
- There is a complete conduction block in the proximal AV node . The atrial stimuli can’t get to the rest of the system
* only has foci at DISTAL end of node, not at proximal
how can the rate of the heart be estimate on the EKG?
Can be estimated by number of cycles (P wave to T wave) seen in one minute
Or counting # heavy lines from R to R
how to estimate HR from R to R
If next R wave one HEAVY line away rate is 300bpm Two lines away 150 bpm Three: 100 bpm Four: 75bpm Five 60 bpm Six: 50 bpm
estimate Rate for someone with bradycardia or an irregular rhythm?
methods for the “normal” person would be inaccurate for these.. so different method:
Each EKG has 3 second marks, count how many cycles for two intervals and multiple by 10
what is the bottom line on the EKG?
rhythm strip
S3 is usually from what? S4 is usually from what?
S3: fluid overload, S4: hardened (non-compliant) ventricle
Sinus arrhythmia (normal variant): how will the EKG look?
- Irregular rhythm
- The distance between P waves varies (hence the irregularity) but still have a P wave before each QRS complex and each P wave is same shape (meaning staring from the same spot, the SA node)
- happens w/ respiration
if the variants for sinus arrhythmia are not met (aka P wave not present, or varying P wave shapes)… what does that mean?
its an ABNORMAL variant and a different type of arrhythmia
what is the QRS axis ?
The direction in which most of the electricity is traveling through the ventricles is called the QRS axis
- measure as circle superimposed on chest and measured in degrees
I at 90 degrees and AVF at 90 degrees (II as a tie-breaker- pos. = normal, neg =left deviation)
hypertrophy will cause the QRS axis to deviate ____ the area of hypertrophy?
towards
infarction will cause the QRS axis to deviate ____ from the area of infarction
away
QRS axis: what degrees constitute the different deviations?
Normal: 0 to +90
Right axis deviation (RAD): +90 to 180 (neg I, pos AVF)
Left axis deviation (LAD): 0 to -90 (pos I, neg AVF)
Extreme axis deviation: -90 to 180 (neg I, neg AVF)
how are time intervals represented on the EKG?
Remember: horizontal axis is time each block is 0.04 seconds
0.20 sec= 5 blocks
0.12 sec=3 blocks
Intervals we look at: PR, QRS, QT
how can you have a STEMI without ST elevation
full thickness injury that has not progressed to cause ST elevation yet. (ST elevation on an EKG shows ischemia)