Bundle Branch Block

Question 1

General rule of thumb of for bundle branch block

Answer 1

Wide QRS complexes

Question 2

Causes of RBBB

Answer 2

• right ventricular hypertrophy
• cor pulmonale
• pulmonary embolism
• myocardial infarction
• atrial septal defect (ostium secundum)
• cardiomyopathy or myocarditis

Question 3

Pathophysiology RBBB

Answer 3

Block in the conduction of the bundle branches, so the ventricles don’t receive impulses at the same time. Right bundle doesn’t conduct. Impulses spreads from left ventricle to right ventricle = LATE ACTIVATION OF RV

Question 4

ECG of RBBB

Answer 4

M = ‘RSR’ pattern in V1 with dominant R
Inverted T waves in V1-V3 or V4
W = Wide slurred S wave in V6
MarroW

Question 5

Auscultation sound for RBBB

Answer 5

Physiological S2 SPLITTING (heart sound)

Question 6

Causes of LBBB

Answer 6

IHD,
HTN,
Valvular disease
Cardiomyopathy,
Idiopathic fibrosis

Question 7

Pathophysiology of LBBB

Answer 7

Block in conduction of one the bundle branches, so the ventricles don’t receive impulses at the same time. Left bundle branch doesn’t conduct. Impulses spreads from RV -> LV
Late activation of LV

Question 8

ECG of LBBB

Answer 8

Dominant S in V1 (W)
‘M’ pattern in V5
Inverted T waves 1, AVL, V5-V6
WilliaM

Question 9

Auscultation sounds of LBBB

Answer 9

Reversed S2 splitting

Question 10

Treatment

Answer 10

Same for both
- Pacemaker
- Cardiac resynchronisation therapy
- Reduce BP