Cardiac Conduction, 12 Lead,
dysrhythmias, and heartblocks.
what happens when a (+) charge moves toward a (+) lead?
upward spike on the EKG
What happens when a (+) charge moves away from the (+) lead?
downward spike on EKG
What does it mean when (-) charge moves towards a (-) electrode?
upward spike in EKG
What causes a flatline on EKG?
either no electrical conduction, or conduction is perpendicular to the axis of the leads
Where are the leads located on lead II?
(-) electrode is on the R arm and (+) electrode is on the L leg
Depolarization and sodium
Sodium goes in the and potassium goes out of the cell causing the interior to become more positive.
Repolarization
potassium goes back into the cell while sodium exits the cell causing it to return to a resting state
Describe the P wave
- This is the SA node sending a charge towards the (+) electrode and depolarizing the atria
Describe the P-R segment
AV node is absorbing all of the (+) charge and not sending it anywhere yet so shows up as a flatline
Describe the Q wave
The septum is depolarizing. This is a downward spike on the EKG because the Left bundle branch is
responsible for this and has net charge moving upward and away from the (+) electrode.
Describe the R wave
This is main part of the ventricles depolarizing. This is the mean flow of charge between the bottom
and bottom sides of the Right and L ventricle. This is a large upward spike on an EKG because the L
ventricle is bigger than the R so pulls it perfectly towards the (+) electrode.
Describe the S wave
This is the depolarization of the base (top) of the ventricles. The mean charge is moving away from
the (+) electrode showing a downward spike on the EKG
Describe the ST segment
, This is a flat line because the ventricles are depolarized and have not yet begun to repolarize
Describe the T wave
Ventricular repolarization. This is shows as an upward spike on the EKG because the negative charge
is pulling away from the (+) and towards the (-) electrode.
What does lead I tell you?
Looks at the lateral wall of the upper left ventricle so tells you the electrical activity of the high
lateral L ventricle
What does lead II and III tell you?
Looks at the heart from the bottom so tells you the electrical activity of the inferior ventricles
Where does aVR look at the heart from?
- Top right down
- Activity of the R ventricle and the Basal Septum (beginning of septum in the middle)
Where does aVL look at the heart from?
- Top Left down.
- high lateral left ventricle wall
Where does aVF look at the heart from?
- base of the ventricles up
What leads tell us about the inferior wall?
Leads II, III, and aVF
What leads tell us about the high lateral wall of the left ventricle
aVL and lead 1
Who is the lone rider and what does it tell us?
aVR- tells us right ventricle and Basal septum
limb leads and augmented unipolar leads show us...
anterior plane
Precordial leads show us...
Horizontal plane. these are unipolar and positive only
How to remember 12 lead limb placement
Ride your Green Bike On Pavement
Red electrode
V1- 4th intercostal at right sternal border
Yellow electrode
dysrhythmias, and heartblocks.
what happens when a (+) charge moves toward a (+) lead?
upward spike on the EKG
What happens when a (+) charge moves away from the (+) lead?
downward spike on EKG
What does it mean when (-) charge moves towards a (-) electrode?
upward spike in EKG
What causes a flatline on EKG?
either no electrical conduction, or conduction is perpendicular to the axis of the leads
Where are the leads located on lead II?
(-) electrode is on the R arm and (+) electrode is on the L leg
Depolarization and sodium
Sodium goes in the and potassium goes out of the cell causing the interior to become more positive.
Repolarization
potassium goes back into the cell while sodium exits the cell causing it to return to a resting state
Describe the P wave
- This is the SA node sending a charge towards the (+) electrode and depolarizing the atria
Describe the P-R segment
AV node is absorbing all of the (+) charge and not sending it anywhere yet so shows up as a flatline
Describe the Q wave
The septum is depolarizing. This is a downward spike on the EKG because the Left bundle branch is
responsible for this and has net charge moving upward and away from the (+) electrode.
Describe the R wave
This is main part of the ventricles depolarizing. This is the mean flow of charge between the bottom
and bottom sides of the Right and L ventricle. This is a large upward spike on an EKG because the L
ventricle is bigger than the R so pulls it perfectly towards the (+) electrode.
Describe the S wave
This is the depolarization of the base (top) of the ventricles. The mean charge is moving away from
the (+) electrode showing a downward spike on the EKG
Describe the ST segment
, This is a flat line because the ventricles are depolarized and have not yet begun to repolarize
Describe the T wave
Ventricular repolarization. This is shows as an upward spike on the EKG because the negative charge
is pulling away from the (+) and towards the (-) electrode.
What does lead I tell you?
Looks at the lateral wall of the upper left ventricle so tells you the electrical activity of the high
lateral L ventricle
What does lead II and III tell you?
Looks at the heart from the bottom so tells you the electrical activity of the inferior ventricles
Where does aVR look at the heart from?
- Top right down
- Activity of the R ventricle and the Basal Septum (beginning of septum in the middle)
Where does aVL look at the heart from?
- Top Left down.
- high lateral left ventricle wall
Where does aVF look at the heart from?
- base of the ventricles up
What leads tell us about the inferior wall?
Leads II, III, and aVF
What leads tell us about the high lateral wall of the left ventricle
aVL and lead 1
Who is the lone rider and what does it tell us?
aVR- tells us right ventricle and Basal septum
limb leads and augmented unipolar leads show us...
anterior plane
Precordial leads show us...
Horizontal plane. these are unipolar and positive only
How to remember 12 lead limb placement
Ride your Green Bike On Pavement
Red electrode
V1- 4th intercostal at right sternal border
Yellow electrode
