ECG Flashcards
How many large squares pass through per minue on an ECG?
300
What is a normal PR length?
0.12-0.2 seconds
What is a normal QRS length?
0.08-0.12 seconds
What is a normal QT interal length?
0.35-0.43 seconds
What may cause a prolonged QT interal?
Drugs
Electrolyte abnormalities (hypokalaemia, hypocalcaemia etc.)
What can cause deviation in the QRS complex?
Venticular hypertrophy (either left or right)
Deviation in the QRS complex is best seen in which leads?
I, II and III
Which distinctive patterns will be present on the ECG for right axis deviation?
- Increases in lead III QRS
- Negative deflection in lead I QRS
The right ventricle now has more influence on the QRS than the left
Which conditions are likely to cause right axis deviation and why?
Pulmonary conditions
e.g. PE
These put strain on the right side of the heart so lead to hypertrophy
How does left axis deviation present on an ECG?
Negative QRS complex in lead III
Negative QRS complex in lead II
What causes left axis deviation?
LVH or a conduction defect
Which area of the heart do leads V1 and V2 “look” at and which pattern do they nrmally observe?
Right ventricle
- Small upward deflection (R wave - septum depolarised)
- Large downward deflection (Q wave - main muscle mass depolarised)
Which area of the heart do leads V5 and V6 “look” at and which pattern do they nrmally observe?
Left ventricle
- Small initial downward deflection (septal Q wave)
- Large upward deflection (R wave - main muscle mass depolarised)
How is it possible to tell on an ECG where the interventricular septum is present?
When R and S waves are roughly equal
That happens around V3/4
How is an ECG reported on? (6)
- Verify patient details
- Check date and time of ECG
- Check paper calibration
- Determine axis
- Look at rhythm strip for: Electrical activity, rhythm, P waves, PR interval, is each P wave followed by a QRS complex, is the QRS of normal duration
- Look at individual leads for volatge criteria changes or ST or T wave changes
