EKG Flashcards
Know this
PR segment?
- Segment preeceeding activation of QRS
- How long it takes for SA node to send signal and AV the ventricle mm fibers to recieve it
- 0.12-0.20 seconds
What is the first negative deflection and second?
- Q
- S
ST segment
- at isoelectric point, may be half mm above
- not normal to be depressed more than half a mm
- ST depression: Subendocardial injury
- ST elevation: subepicardial or transmural injury
- not normal to be depressed more than half a mm
- period between QRS and T wave, how long ventricles are depolarizing
QT interval
- should be less than half of previous R-R interval
- Length of time during ventricular systole
How should the P wave look on 1,2, (limb leads) and V4,V6 (chest leads), AVF, AVR?
- Upright in 1,2,V4,V6, AVF
- Inverted in AVR
ORS complex, describe Q wave
- Q wave not greater than 0.03 in width
- Q waves are small and narrow in AVL, AVF, V5 and V6
Describe T wave direction in different leads?
- Upright in 1,2,V3-V6
- Inverted in AVR
- Variable in 3, AVL, AVF, V1-2
- height not greater than 5 mm in standard leads or 10mm in precordial leads
What is the T wave assoc with when it is inverted or very tall and peaked?
- Inverted: ischemic pattern
- Tall: hyperkalemia
Where do lead 1, AVL, V5 V6 pick up information and 2,3,AVF and
V1-4?
- 1, AVL, V5 V6 are lateral wall heart
- 2,3,AVF components in inferior diaphragmatic portion
- V1-4 pick up activity over anterior portioin
What can shorten a PR interval?
- AV jxnl and low atrial rhythms
- Wolff parkinson white syndrome
- Lown ganong levine syndrome
- Glycogen storage disease
- Htn
- normal variationi
- D is right bundle branch block
- Inverted Q previous MI
- Picture shows variation, you can have R waves with no Q, inverted waves, and missing waves
If there is no Q wave can you have an R wave?
Yes, first up right deflection is R whether there is a Q wave or not
ST segments
This is all artifact
What are the best leads for reading P waves?
Lead II and V1
On the ECG each dark line represents __ and each smaller box represents ___.
- 0.20 sec
- 0.04 sec
What is the rate?
- ~125 BPM
- each big line is 300 150 100 75 60 50 43
- HR per min =300 divided by # large squares
Rate
- physiologic sinus arrythmia, this is normal as you inhale rate increases and exhales as you decrease
- second R wave ~75 BPM
What could be going on if P wave comes after QRS? What is rate?
- SVT
- Junctional rhythm seen in the picture
- rate is ~65-70 BPM
What is 1 2 and 3 perpendicular to?
- 1 perpendicular to AVF
- 2 perpendicular to AVL
- 3 perpendicular to AVR
What is axis?
- look at AVF, is it running positive or negative
- Look at Lead I, is it positive or negative
- axis is btw 0 and 90 as both are positive
Normal axis should have positive deflection of leads ___ &___.
- lead I and aVF
Describe what a left axis looks like.
- If lead one is positive and aVF is negative
Describe right axis
- negative lead I
- Positive aVF
Lead I is positive and aVF is negative, what is the axis?
left axis (-30 to -90)
rate? axis?
Rate: ~40 BPM
rate and axis?
- ~75 bpm
- 1 and F are both positive so normal quadrant
- aVR perpendicular to lead III
- +30 degrees
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