Dysrhythmias Flashcards
Cardiac Muscle Cells do 4 things
Automaticity
Excitability
Conductivity
Contractility
Automaticity
Ability to generate an electrical impulse
Excitability
ability to respond to an outside impulse (chemical, electrical, mechanical)
Conductivity
Ability to receive an electrical impulse and conduct it
Contractility
Ability of myocardial cells to shorten in respond to an impulse (muscle cells)
Atrial Depolarization
P-Wave
(Atriums squeeze)
Atrial systole
Ventricle Depolarization
QRS Complex
(Ventricles squeeze)
Ventricular systole
Repolarization
FILLING
Atrial Repolarization:
within QRS complex
Ventricular Repolarization:
T-Wave
Action Potential
Sodium + Potassium mediated (atp pump)
SA Node
Stimulates Atria to contract (P-Wave)/atrial depolarization
AV Node
Stimulates Ventricles to contract
(QRS)/Ventricular depolarization
Electrical Conductivity of Heart
- SA node
- Atrial Depolarization
- AV node
- Ventricular Depolarization
- Ventricular Contraction
- Ventricular Repolarization
- Nothing
- SA node…..
Bundle of His + Purkinje Fibers
Tell Ventricles to do their thing
Normal Electrical Conductivity of Heart (Sinus Rhythm)
SINUS RHYTHM:
Rate: 60-100
Rhythm: Regular
P-Wave:
- Upright + rounded
- One before every QRS
- Regular rhythm
PR interval:
-0.12-0.20 sec
QRS: < 0.12 sec
PR Interval time (sinus rhythm)
0.12-0.20 sec
QRS time (sinus rhythm)
< 0.12 sec
Sinus Arrhythmia
A degree in variability in the HR
- Common among young people
- HR fluctuates with respiration or autonomic nervous system
*Intervals P-P are different
