Summary EKG rhythms summaries for exam Preparation

EKG rhythms summaries for exam Preparation

1. cardiac
SA node ’ AV node ’ bundle of His ’ right & left
conduc- tion
bundle branches ’ purkinje fibers
pathway
SA node: atrial depolarization

AV node: slows conduction, allows blood to travel
from ventricles to atria

SA node = lead pacemaker, fastest
2. overdrive
sup- pression
overdrive suppression = SA node silences other
auto- maticity foci

SA node fails ’ backup foci take

over irritable foci can produce rapid

pace

3. P wave duration <0.12s

3 SMALL SQUARES




4. QRS complex narrow (normal) <0.1s (<1/2 large box)

broad >0.1s (>1/2 large box) [pic]




5. T wave limb leads <5mm


,EKG rhythms summaries for exam Preparation

precordial leads

<10mm






, EKG rhythms summaries for exam Preparation




6. PR interval duration 0.12-0.2s

3-5 SMALL SQUARES (<1 box)




7. QT interval <1/2 preceding RR interval

prolonged:
-men >440ms
-women >460ms

> 500 ’ risk of deadly arrhythmia

8. regular consistent rhythm
sinus rhythm
constant, consistent cardiac cycles of equal length




9. sinus arrhythmia normal physiological variant

gradual increase & decrease in HR

related to thoracic pressure changes while
breathing