CV 4 Flashcards
When do you get an upward deflection?
When you have a wave of positive charge (depolarization) moving towards a positive electrode
Also when you get repolarization moving away from a positive electrode
Charges and locations for
- Lead I
- Lead II
- Lead III
- Right arm negative, left arm positive
- Right arm negative, left leg positive
- Left arm negative, left leg positive
aVF
Augmented voltage (left) foot
Left foot is positive electrode
Right AND left arms are negative
aVR
Augmented voltage right arm
Right arm is positive electrode
Left arm and left foot are negative
aVL
Augmented voltage left arm
Left arm is positive electrode
Right arm and left foot are negative
Where do the leads record?
- V1 and 2
- V3 and 4
- V5 and 6
- Right side of heart
- Septum
- Left ventricle
Wolff Parkinson White syndrome
Accessory pathway for conduction through the heart
Bypasses the AV node (no pause)
Delta wave
Bump at the start of the QRS wave from the extra conduction
May not see it on every lead
SA node controls ____
AV node controls ____
HR
Conduction velocity
What drug do you give to treat WPW syndrome?
Adenosine
It slows conduction through the AV node
Othodromic
Narrow tachycardia
Uses the regular conduction pathway in the ventricle (purkinje fibers are really fast and the system is properly organized)
Antidromic
Wide tachycardia
Loop goes in opposite direction (signal is trying to travel through the muscle_
Maximum heart rate
220 - age
How does slowing conduction through the AV node lead to conversion to normal rhythm?
The refractory period in the node lasts longer, so when the loop arrives back at the AV node it is in the refractory stage
Will not conduct the signal, so the cycle is broken
