This document discusses right bundle branch block (RBBB). It defines RBBB and its diagnostic criteria. Potential causes of RBBB are listed, including pulmonary embolism and ischemic heart disease. The document notes that RBBB is generally not clinically significant in asymptomatic patients and has little impact on prognosis, though it can indicate issues in patients with symptoms like chest pain or dyspnea. Large studies have found no association between RBBB and increased mortality in otherwise healthy individuals.

1. ECG
WORKSHOP
Southern Philippines Medical Center
Internal Medicine Department

2. Electrical Activation of the
Heart
SA Node
60-100 bpm
AV Node
40-60 bpm
Ventricle
20-40 bpm

4. Electrical Activation of the
Heart

5. Bundle Branch
Blocks

7. Right Left

14. Delayed RV activation -
secondary R wave (R’) in
the right precordial leads
(V1-3)
Wide, slurred S wave in
the lateral leads.
Delayed activation of the
RV  ST depression and
T wave inversion in the
right precordial leads.

15. DIAGNOSTIC CRITERIA OF
RBBB
Broad QRS > 120 ms
RSR’ pattern in V1-3 (‘M-shaped’ QRS complex)
Wide, slurred S wave in the lateral leads (I,
aVL, V5-6)

17. • Right ventricular hypertrophy / cor
pulmonale
• Pulmonary embolus
• Ischemic heart disease
• Rheumatic heart disease
• Myocarditis or cardiomyopathy
• Degenerative disease of the conduction
system
• Congenital heart disease (e.g. atrial
septal defect)

18. CLINICAL SIGNIFICANCE
OF RBBB
RBBB in asymptomatic – NOT correlated
with adverse outcomes.
New RBBB in patients with chest pain - may
indicate occlusion in the left anterior
descending artery.
New RBBB in patients experiencing dyspnea
(particularly if acute) - may indicate
pulmonary embolism.
In the vast majority of cases, however, RBBB
is a benign finding with little if any impact of
cardiovascular prognosis.

19. A large prospective cohort study
evaluated the association between
RBBB and mortality over a period of
20 years in otherwise healthy
individuals; NO ASSOCIATION was
found.
CLINICAL SIGNIFICANCE
OF RBBB

20. Right Left

26. R to L overall depolarization
 tall R waves in the lateral
leads (I, V5-6)
 deep S waves in the right
precordial leads (V1-3)
 LAD
The ventricles are activated
sequentially (right, then left)
rather than simultaneously
 a broad or notched (‘M’-shaped)
R wave in the lateral leads.

27.  QRS duration of > 120 ms
 Dominant S wave in V1
 Broad monophasic R wave in lateral leads (I, aVL, V5-V6)
 Absence of Q waves in lateral leads (I, V5-V6; small Q waves are still
allowed in aVL)
 Prolonged R wave peak time > 60ms in left precordial leads (V5-6)

29. Appropriate discordance: the ST
segments and T waves always go in the
opposite direction to the main vector of
the QRS complex
Poor R wave progression in the chest
leads
Left axis deviation

32. Aortic stenosis
Ischaemic heart disease
Hypertension
Dilated cardiomyopathy
Anterior MI
Primary degenerative disease (fibrosis) of
the conducting system (Lenegre disease)
Hyperkalaemia
Digoxin toxicity

33. 1. Asymptomatic patients, LBBB appears to
have minimal effect on outcomes in younger,
apparently healthy subjects,
 LBBB in older individuals has been
associated with an increase in
mortality
2. LBBB is an independent predictor of all-
cause mortality in patients with known or
suspected coronary heart disease

34. 3. The presence of LBBB is associated with
higher short-term and long-term mortality
following a myocardial infarction
4. LBBB is an independent risk factor for
mortality in patients with heart failure and is
associated with increased all-cause mortality
and sudden death at one year
5. For asymptomatic patients with an isolated
LBBB and no other evidence of cardiac
disease, no specific therapy is
required.

35. Fascicular Blocks

42. NO EVIDENCE OF RIGHT
VENTRICULAR HYPERTROPHY
NO EVIDENCE OF ANY OTHER
CAUSE FOR RIGHT AXIS
DEVIATION

47. Thank you!