ECG Graph Flashcards
what does the P wave show?
atrial depol
what does the QRS complex show?
ventricular depol
what does the T wave show?
ventricular repol
why is atrial repol not seen on an ECG?
masked by ventricular depol
what creates the PR interval?
AV node delay
what creates the ST segment?
ventricular systole
what creates the TP interval?
diastole
which lead is used as the rhythm strip?
lead II
length and height for P wave?
<3mm
<2.5mm for height
length for QRS?
3 small squares
length for PR interval?
3-5 small squares
how to work out heart rate?
300/large squares between beats OR large squares between R-R interval
label
positions of V1-V6?
V1 - 4th ICS left sternal edge
V2 - 4th ICS right sternal edge
V3 - between 2 and 4
V4 - 5th ICS mid clav line
V5 - anterior axillary line, same level as V4
V6 - mid axillary line, same level as V4
how to calculate rate?in tachycardia?
300/large squares between R complexes
1500/small squares between R complexes
how to calculate rate in irregular rhythms?
number of QRS complexes in 30 large squares x10
to determine the cardiac axis, what leads are examined?
I
aVF
in normal axis, what are lead 1 and aVF?
positive
positive
in left axis deviation , what are lead 1 and aVF?
aVF - negative
lead I - positive
in right axis deviation , what are lead 1 and aVF?
lead I - negative
aVF - positive
what would mean there was an indeterminate axis?
negative
negative
how long is a
small box
large box
5 large boxes?
- 04
- 2
1 second
what lead can P waves be inverted in, and it is still normal?
aVR
what is an R wave?
first upward deflection, even if not followed by a Q
what pattern should R waves follow?
increase in amplitude from V1-6
what is the rule for T waves?
should not be more than half the size of the preceding QRS
how to calculate the length of QT interval?
square root of (R-R interval in seconds/QT interval in ms)
