ECG

Question 1

How many large squares pass through per minute on an ECG?

Answer 1

300

Question 2

What is a normal PR length?

Answer 2

0.12-0.2 seconds

Question 3

What is a normal QRS length?

Answer 3

0.08-0.12 seconds

Question 4

What is a normal QT interal length ?

Answer 4

0.35-0.43 seconds

Question 5

What may cause a prolonged QT interal?

Answer 5

Drugs
Electroylte abnormalities (hypokalaemia, hypocalcemia etc)

Question 6

What can cause deviation in the QRS complex?

Answer 6

Ventricular hypertrophy (either left or right)

Question 7

Deviation in the QRS complex is best seen in which leads?

Answer 7

I, II and III

Question 8

Which distinctive patterns will be present on the ECG for right axis deviation?

Answer 8

• Increase in lead III QRS
• Negative deflection in lead I QRS
  The right ventricle now has more influence on the QRS than the left

Question 9

Which conditions are likely to cause right axis deviation and why?

Answer 9

Pulmonary conditions
e.g. PE
These put strain on the right side of the heart so lead to hypertrophy

Question 10

How does left axis deviation present on an ECG?

Answer 10

Negative QRS complex in lead III

Negative QRS complex in lead II

Question 11

What causes left axis deviation?

Answer 11

LVH or a conduction defect

Question 12

Which area of the heart do leads V1 and V2 “look” at and which pattern do they normally observe?

Answer 12

Right ventricle

• Small upward deflection (R wave- septum depolarised)
• Large downward deflection ( Q wave- main muscle mass depolarised )

Question 13

Which area of the heart do leads V5 and V6 “look” at and which pattern do they normally observe?

Answer 13

Left ventricle

• small initial downward deflection (septal Q wave)
• Large upward deflection (R wave - main muscle mass depolarised)