10-24-14 Cardiac AP & ECG Flashcards
An upward stroke on an ecg indicates ______
depolarization towards a lead
A flat line on an ECG results because of ______
no current flowing to that specific lead
A depolarizing current producing a negative reflection is moving in which direction with respect to the specific lead?
Away from the lead = negative reflection
A repolarizing current moving towards a lead produces which kind of deflection?
A negative deflection
A repolarizing current moving away from a lead =
positive deflection
Standard ECG = 1 mv = ____ mm
10 mm, 10 small squares
Where is V1 placed?
Anterior chest 4th intercostal space
Where is V6 placed?
5th intercostal space lateral chest
The magnitude of the signal is directly proportional to _____
the amount of muscle
the more muscle present, the more
signal generated
What direction does the depolarizing wave move in the ventricle walls?
Subendocardial to epicardial wall
Repolarization moves what direction in the ventricular walls?
Epicardium to endocardium
What does Concordant refer to in qrs & T waves?
A positive qrs wave usually corresponds to a positive T wave, or a negative qrs wave with a negative T wave
Repolarizing is towards or away from a lead?
Away
A depolarizing wave is towards or away from a node?
Towards
What is this?
The SA & AV node AP
What happens at phase 4
- Spontaneous Depolarization
- Special/funny Na+ channels open
What is happening at phase 0
Slow Ca2+ channels open
Special K+ channels close
What is happening at phase 3
Closing of Ca2+ gates
Special K+ gates open
In general, what does an open K+ channel mean?
The cell is at, or moving towards, its resting potential
What is the drawing depicting?
Atrial and Ventricular depolarization
What is happening at phase 4?
- High gK+
- AKA K+ channels are open and K+ is leaving the cell
What is happening at phase 0
Na+ gates are opening
What is happening at phase 1
- Na+ gates close
- Some K+ gates open
