8 ECG WORKSHOP BUNDLE BRANCH BLOCK & FASCICULAR BLOCK.pptx

ECG Bundle Branch Block
Fascicular Block

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

3. Electrical Activation of the Heart

4. Bundle Branch Blocks

5. Bundle Branch Block Right Left

6. rbbb

7. rbbb

8. rbbb

9. rbbb

10. rbbb

11. 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 .

12. 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)

13. Causes of RBBB • 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)

14. 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 .

15. 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

16. Bundle Branch Block Right Left

17. lbbb

18. lbbb

19. lbbb

20. lbbb

21. Left Bundle Branch Block 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 .

22. ECG Diagnostic Criteria 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)

23. Associated Features 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

24. Causes of Left Bundle Branch Block Aortic stenosis Ischaemic heart disease Hypertension Dilated cardiomyopathy Anterior MI Primary degenerative disease (fibrosis) of the conducting system ( Lenegre disease) Hyperkalaemia Digoxin toxicity

25. Clinical Significance 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

26. 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 .

27. Fascicular Blocks

28. Fascicular Blocks

29. - Inferior lv is activated first - Marked left axis deviation

30. No evidence of right ventricular hypertrophy No evidence of any other cause for right axis deviation

31. Overview of intraventricular conduction blocks

32. Thank you!