ECGs Flashcards
What are the normal dimensions of a P-wave?
0.1 seconds duration, 2.5mm high
How tall is a normal T-wave?
5-10mm
In which leads are T-waves always positive in a normal ECG?
Lead I
Lead II
aVF
V2-V6
T-waves can be inverted in V1-4 in children or V1-3 in adults and this can be normal.
What are U-waves indicative of?
Late repolarisation of the Purkinje fibres.
To estimate heart rate quickly, approximately what is the heart rate if there are a) 1 large square b) 2 large squares c) 3 large squares d) 4 large squares e) 5 large squares f) 6 large squares between the R-waves?
a) 30
b) 150
c) 100
d) 75
e) 60
f) 50
What does this ECG show?
Right Bundle Branch Block
What are the features of Right Bundle Branch Block on an ECG?
V1 - M shaped ST segment
V6 - Prolonged QRS
(Marrow)
What does this ECG show?
Left Bundle Branch Block
What are the features of Left Bundle Branch Block on an ECG?
V1 - prolonged QRS complex
V6 - M shaped QRS complex
(William or Vilhelm)
What does this ECG show?
First degree AV block
What are the features of a first degree AV block on an ECG?
Prolonged PR interval of more than 0.2 seconds.
What are some causes of a first degree AV block?
Coronary heart disease
Inferior wall MIs
Hyperkalaemia
Congenital abnormalities
Drugs e.g. beta blockers, digitalis and ccbs
What is the difference between second degree AV block type 1 and type 2?
Increasingly prolonged PR interval in type 1
Only ventricular rhythm is irregular in type 1
QRS complex may be normal for type 2 but can drop off in type 1
What are some causes of second degree AV block type 1?
Acute inferior wall MI
Drugs e.g. beta blockers, digitalis and ccbs
What are some causes of second degree AV block type 2?
Acute anterior wall MIs
Anteroseptal myocardial infarction
Cariomyopathy
Rheumatic heart disease
Coronary artery disease
Drugs e.g. beta blockers, digitalis and ccbs
Which type of second degree AV block is more dangerous?
Type 2 because it can progress to third degree complete block.
What are the features of third degree complete block on an ECG?
Regular P-P intervals
Regular QRS to QRS intervals
However, these two are not linked or regular when compared to each other.
What are some causes of third degree complete block?
Acute inferior and anterior myocardic infarction
Coronary heart disease
Excessive vagal tone
Myocarditis
Endocarditis
Age
Oedema from heart surgery
Medication toxicity from digitalis, beta blockers, ccbs
What does systemic ST elevation indicate?
Pericarditis
What should you always assume ST elevation indicates unless proven otherwise?
MI
