Understanding the ECG Flashcards
What is the value of the standard sweep speed?
25 mm/s
What are some of the things ECGs can be used to identify?
tacharrhythmias bradyarrhythmias MI Myocardial ischaemia Cardiomyopathy
Which limb has the grounding lead?
right leg
Which limbs are connected by lead 1? Which electrode is positive and which negative?
right arm to left arm
R - negative
L - positive
Which limbs are connected by lead 2? Which electrode is positive and which negative?
right arm to left leg
R - negative
L - positive
Which limbs are connected by lead 3? Which electrode is positive and which negative?
left arm to left leg
A - negative
L - positive
What do the three leads form?
Einthoven’s triangle
What are the two components of the augmented leads?
Only one electrode is a true electrode (positive), the other is an average of two electrodes
Which electrodes are positive and negative in aVR lead?
right arm is positive,
average of left arm and left leg is negative
Which electrodes are positive and negative in aVL lead?
left arm is positive,
right arm and left leg average is negative
Which electrodes are positive and negative in aVF lead?
left leg is positive,
right arm and left arm average is negative
At which angle do the augmented and 3 leads go?
lead 1 = 0 degrees lead 2 = 60 aVF = 90 lead 3 = 120 aVR = 210 aVL = -30 (330)
What is the range for normal QRS axis, left axis and right axis?
normal QRS axis = -30 to 90 degrees
right axis = 90 to 180
left axis = -30 to -90
Which 2 leads can be used to find QRS axis?
Lead 1 and aVF lead (must be at 90 degrees)
How is QRS axis calculated?
Find the angle between by findings number of squares in each side and use tan
