CXR and ECG

Question 1

Approach to CXR analysis

Answer 1

Assessment
- Verify Patient name, DOB, date of exam
- Exposure (fine lung markings should be visible)
- Rotation
- Expansion

ABCDEFG:
1. Air where it shouldn’t be (under diaphragm, pneumothorax, mediastinum, skin)
2. Bones
3. Cardiac silhouette and size
4. Diaphragm
5. Effusion and Equipment (ETT, NGT, ECG)
6. Fields (lung fields) - should be symmetric without haziness, blotches or dots
Great vessels

Question 2

DDX for white out on CXR

Answer 2

• Consolidation: trachea MIDLINE, contralateral lung normal, ribs normal, may see air bronchograms
  • Collapse: Trachea pulled towards SAME side, crowding of ribs in affected side, contralt lung is hyperinflated
  • Fluid (effusion): trachea midline or towards OPPOSITE side, contralateral lung will be normal/collapsed, meniscus effect
  • Mass: trachea midline or towards OPPOSITE side, contralateral lung will be normal/collapsed, rounded appearance to lesion
  • Lobectomy or atresia - trachea towards SAME side, hyper inflated contralateral lung, may see staples post lobectomy

Question 3

ECG analysis

Answer 3

1. Rate = 300/(large boxes between QRS)
2. Rhythm
3. Axis - look at leads I, II, AVF
   1. QRS axis
      
      1. Normal values
         
         1. 0-1: RAD (NEG I/POS AVF)
         2. > 1YO: NORMAL AXIS (POS 1/POS AVF)
   2. P wave axis - normal if positive p wave in I, and aVF
      
      1. Low atrial rhythm if neg in II and or AVF
   3. Segments
      
      1. P wave
         
         1. Bifid or long = LA enlargement
         2. High/peaked = RA enlargement
      2. PR interval
         
         1. Duration= 3-5 small squares (120-200ms)
            
            1. > 200ms = heart block
            2. <120ms = pre-excitation
      3. QRS
         
         1. Duration = < 3 small squares (<120ms)
            
            1. Narrow = Supraventricular
            2. Broad = ventricular
         2. Height
            
            1. Tall V1-3: RVH
            2. Tall V4-6: LVH
         3. Morphology
            
            1. Delta wave = WPW
      4. T wave
         
         1. Progression
            
            1. Inversion V1-3 at birth which progressively revert in reverse order
            2. Persisent inversion of V1 after 8yo is normal
      5. ST segment (should be isoelectric)
      6. QT
         
         1. Should be < 1/2 RR interval

Question 4

ASD

ECG, CXR and clinical findings in a 5yo

Answer 4

Incomplete RBBB
ESM at upper LSE
CXR - cardiomeg (RV hypertrophy)
plethora
prominent PA
Fixed split S2

Question 5

ECG features L ventricular hypertrophy

Answer 5

Large R wave voltages in V5, V6
Deep S wave in V1
(note normal ranges change with age)
LAD

Question 6

4/6 pan systolic murmur at LSE

Answer 6

VSD (voltages due to L ventricule dilation which normalises over time)

Question 7

VSD

ECG, CXR findings

Answer 7

CXR - cardiomegaly, pulmonary plethora, hyper expanded lungs
ecg - rvh, lvh

Question 8

R ventricular hypertrophy ecg findings

Answer 8

rad
R wave dominance v1
S wave dominance V5, V6
upright t wave v1

Question 9

loud systolic murmur
mild cyanosis 88%
R V hypertrophy

?what heart defect

Answer 9

TOF pre op

Question 10

What do tall p waves indicate?

Answer 10

Right atrial dilatation/hypertrophy

Question 11

LONG bifid p wave in lead II

Answer 11

L atrial dilatation/hypertrophy

Question 12

Conditions that cause R atrial hypertrophy

Answer 12

Large ASD

Question 13

Conditions that cause left atrial hypertrophy

Answer 13

Mitral regurgitation or stenosis
Large VSD or duct
Cardiomyopathy

Question 14

Causes of L axis deviation

Answer 14

LVH esp with volume overload (large VSD)
LBBB (wide QRS)
Tricuspid atresia
AV canal defect

Question 15

R atrial enlargement = what on ECG?

Answer 15

p wave hight >3mm (3 small squares)

Question 16

L atrial enlargement = what on ECG?

Answer 16

bifid p waves
prolonged > 10ms (2.5 small squares)

Question 17

What condition is assoc w Extreme axis deviation?

Answer 17

AVSD