Cardio - ECG Pathology, QRS wave abnormalities

Question 1

Definition of a wide QRS?

Answer 1

> 0.12s

Question 2

Wide QRS differentials

Answer 2

LBBB and RBBB - WilliaM MarroW

Hyperkalaemia

V-Tach

WPW

Meds - TCAs

Paced rhythm

Question 3

LBBB

Answer 3

Question 4

RBBB

Answer 4

Question 5

Where do you find pathological Q waves, what are they, and what are the differentials?

Answer 5

Never seen in V1-V3 - so if you see them here, then pathological

Pathological Q wave criteria:

• Wide >0.04s OR
• >2mm in depth OR
• Measure distance between isoelectric line and Q wave, and height of QRS complex, if Q wave greater than 25% of height of QRS complex - pathological Q wave

Differentials:

1. MI
2. PE
3. LBBB
4. LVH

Question 6

Low voltage QRS complexes - what are they, differentials

Answer 6

Take and add up R waves in leads I, II, III, and if it is less than 15mm - low voltage QRS

Do same thing in V1-3, and if it is <30mm, could be a sign of low voltage QRS

Differentials:

1. Obesity
2. COPD
3. HF
4. Pericardial effusion
5. Infiltrated diseases - sarcoidosis

Question 7

R wave progression:

Answer 7

R waves should increase in size from V1-V6

If there isn’t great increase, sign of poor R wave progression

Differentials:

1. Anterior MI
2. Ventricular hypertrophy w/ strain

Question 8

Dominant R waves, what are they, differentials

Answer 8

If R waves in V1-3 are big - not supposed to be, should be small

If you see ST-depression and upright T waves, then thinking, differentials:

1. Posterior MI
2. RBBB
3. RVH

Question 9

LVH

Answer 9

1. Add together S wave in V1 and V2 (add together what should be a big number in V1-2, so S wave)
2. Add together R wave in V5 and V6 (add together what should be a big number in V5-6, so R wave)
3. If answer is greater than 35mm, sign of LVH

Question 10

RVH

Answer 10

R waves should not be big in V1 to V3

S wave should not be big in V5 to V6

1. Add R wave in V1 and V2
2. Add S wave in V5 and V6
3. Opposite of what you do to measure LVH
4. If answer is greater than 10mm, then RVH

Question 11

QT interval - prolonged QT figures in male and females, and differentials

Answer 11

Prolonged QT:

1. Long in females - >460ms
2. Long in males - >430ms

Differentials:

1. Hypokalaemia
2. Hypomagnesemia
3. Hypocalcaemia
4. Ischaemia
5. Drugs:
   
   1. Antiarrhythmics
   2. Antibiotics
   3. Antipsychotics
   4. Antidepressants
   5. Antiemetics

Question 12

What does a prolonged QT interval increase the risk of?

Answer 12

Torsades de pointes

Question 13

QT interval - short QT interval figure and differentials?

Answer 13

Short <350ms

Differentials:

1. Hyperkalaemia (opposite of prolonged QT hypoK+)
2. Hypermagnesemia (opposite of prolonged QT hypomag)
3. Digoxin therapy

Question 14

What is Wellens Syndrome?

Answer 14

Wellens Syndrome is a clinical syndrome characterised by biphasic or deeply inverted T waves in V2-3, plus a history of recent chest pain now resolved

It is highly specific for critical stenosis of the left anterior descending artery (LAD)