EKG Module #1 Flashcards
How do you use Box Method to calculate Heart Rate?
300-150-100-75-60-50
- Box method: Count thick/black lines (boxes) in between 2 R waves. Can use this when rhythm is regular
Sinus Bradycardia
<60bpm. Impulse originates at SA node at a slow rate
Sinus Tachycardia
> 100bpm. Impulses originate at SA node at rapid rate
How do you use QRS complexes to calculate rate?
- count the number or R waves in the entire strip. If 10sec strip multiply by 6, if 6sec strip multiply by 10. Can use this when rhythm is Slow or Irregular.
What are the 2 components of rhythm?
Sinus vs. Non sinus
Regular vs Irregular
What are the sinus criteria?
- P wave before every QRS
- Normal P waves should be upright in leads I and II but inverted in AVR
Normal sinus rhythm
impulses originate in SA node at a normal rate
- P waves haves to have the same size/morphology
Sinus Arrhythmia
Irregular rhythm. Influenced by expiration. Normal variant
- Impluse originates at SA node. Rate is Variable!
- R- R progressively gets longer during exp, & shortens w/ isnoiration
- All complexes normal, rhythm is irregular. Longest R-R interval exceeds shortest >0.16sec
Pathway of electrical signaling through the heart
SA node—>Atrial syncytium—>Junctional fibers—>AV node—>AV bundle—>Bundle branches–>Purkinje fibers—>ventricular syncytium
AV blocks 1st, 2nd,3rd degree
-Delay/block signal from SA node
PR interval length
0.12-0.20sec
3-5 small boxes
*Time it takes for stimulus to spread through atria and pass through AV junction
How do you measure PR interval?
From beginning of P wave to beginning of QRS complex (really PQ interval)
2nd degree AV block
Progressive lengthening of PR interval
QRS complex
0.08 - 0.12sec
2-3 small boxes
*Time it takes for signal to travel through ventricles
How do you measure QRS complex?
From beginning of Q wave to the end of the S wave
