ECG Flashcards
What does the p wave represent?
Atrial depolarisation
What does the QRS wave represent and why is the R so tall?
Ventricular depolarisation
R wave- ventricular depolarisation directly toward the apex of a large amount of muscle
What does LV hypertrophy show on ECG?
Taller R wave
Which way is the IV depolarisation and which ECG wave depicts it?
Left to right
Q wave
Why is the S wave a small downward defection?
Down ward because electrical activity moving away from apex and small because not directly away- oblique.
Why is the T wave upright when viewed from the apex?
Depolarisation moving away from apex
12 lead ECG has how many leads?
10=
6 chest
+
4 limb
Which three leads look at the inferior heart?
II, aVF, III
Which lead looks from the right shoulder obliquely?
aVR
Which leads looks across the heart horizonatlly heart from the left limb?
I
The oblique view of the heart from the shoulder is given by lead….
aVL
The limb leads look at the heart in the ….. plane
vertical
Which leads look at the left side of the heart?
I and aVL
Which chest leads look at the right ventricle and septum?
V1 and V2
Which chest leads are looking at the apex and ant wall of heart?
V3 and V4
Which chest leads look at the LV?
V5 and V6
Name the 4 lateral leads.
aVL, I, V5 and V6
What time scale does one small square equate to on an ECG?
0.04 s
0.2s is depicted by what on an ECG
A big square
Why do we look at 30 large squares to get a rate in irregular rhythms?
30 large squares is 6 seconds so can times by 10 to get bpm
How do we count the beats?
R-R cycles
In a regular rhythm how do you get a rate?
Look at R-R interval
eg 4 big boxes
300 big boxes is a minute so how many lots of 4 boxes could you fit in 300 and thats your HR
How do you measure a PR interval?
Start of P wave to start of Q wave.
If a PR wave is >3-5 small boxes it signals….
ischaemia
The QRS interval is the …. of the QRS complex and should be less than….s which is … boxes
width
0.12s
3 small boxes
What ECG element varies with heart rate?
QT interval so we correct for it
How do you measure a QT interval and whats the upper limit of normal?
Starts of Q to the end of T
0.45s in men 0.47s in women
What must you check to confirm sinus rhythm?
Rhythm regular P wave present P wave upright in leads I and II PR interval 3-5 small boxes P wave always followed by QRS QRS not wider than 3 small boxes.
Can you be in sinus rhythm but have tachycardia or bradycardia?
Yes sinus tachycardia and sinus bradycardia can happen
