ECG Flashcards
1
Q
y-axis
A
voltage
2
Q
x-axis
A
time
3
Q
positive deflection =
A
net current flow towards lead
4
Q
baseline =
A
isoelectric point, no net current flow in direction of lead
5
Q
negative deflection =
A
net current flow away from lead
6
Q
1 big square =
A
0.5 mV or 0.2 seconds
7
Q
typical settings
A
- Speed = 25 mm/sec
- Voltage = 10mm/mV
- One small square = 1mm x 1mm
- One big square = 5mm x 5mm
- Standard ECG Is 25 cm
- 5 big squares = 25mm = 1 second
8
Q
p wave
A
atrial depolarisation
9
Q
QRS complex
A
ventricular depolarisation
10
Q
T wave
A
ventricular repolarisation
11
Q
PR interval
A
Normal values:
• 120-200 ms
• (3 to 5 small squares)
12
Q
QRS complex width
A
Normal values:
• Less that 120 ms
• 3 small squares
13
Q
QT interval
A
• Measure of time to ventricular repolarisation • Time from onset of QRS to end of T Normal values: • Men 350-440 ms • Women 350-460 ms
14
Q
bipolar lead
A
measures the potential difference between 2 electrodes
one electrode designated positive the other negative
15
Q
unipolar lead
A
measures the potential difference between an electrode and a combined reference electrode
sometimes known as augmented leads
