Exam | Bon Secours Mercy Health
Nursing Education
Blood flow through the heart
SVC --> Rt atria --> Tricuspid --> Rt ventricle --> Pulmonic valve --
> Lungs --> Lt atria --> Mitral valve --> Lt ventricle --> aortic valve
--> aorta --> Body
EKG Times
6 second strip
1 small block = 0.04 secs
1 big block = 5 small boxes = 0.20 secs
15 big blocks = 3 seconds
P Wave
atrial depolarization
PR Interval
time it takes for the impulse to get from atrial to ventricles
0.12 - 0.20 seconds
QRS Interval
ventricular depolarization
< 0.12 seconds
ST Segment
early depolarization of ventricles
depression = myocardial infarction
elevation = myocardial injury
T Wave
repolarization of ventricles
Heart blocks
No changes in PR Interval
- QRS complexes present = 1st degree
- No QRS complexes = 2nd degree type II
, Changes in PR Interval
- R to R interval regular = 3rd degree
- R to R interval irregular = 2nd degree type I
Conduction pathway
Sinus node - inerarterial tracts - atrium - intermodal tracts - AV
node - bundle of HIS - bundle branches - purkinje fibers -
ventricles
Inherent rates
SA node = 60-100
AV node = 40-60
Ventricle = 20-40
Atrial flutter
Sawtooth pattern
Atrial fibrillation
Waves between QRS
Supraventricular tachycardia
No P wave, rate > 150
Junctional rhythms
P wave inverted or absent
Junctional bradycardia: < 40
Junctional rhythm: 40-60
Accelerated junctional: 60-100
Junctional tachycardia: > 100
Ventricular tachycardia
marching nuns
Torsades de pointes
Rate > 200, no P waves, wide QRS
Ventricular fibrillation
Rate cannot be counted
Idioventricular
Rate 20-40
T wave opposite QRS, no P wave, wide QRS
Accelerated Idioventricular
Rate 40-100
T wave opposite QRS, no P wave, wide QRS