1. The document discusses electrocardiogram (ECG) patterns seen in bundle branch blocks (BBB) and how they can mask signs of myocardial infarction (MI). 2. It outlines modified Sgarbossa's criteria for diagnosing MI in the presence of left bundle branch block (LBBB), focusing on concordance and discordance between ECG deflections. 3. Several case examples are provided to demonstrate applying the concepts of BBB patterns and Sgarbossa's criteria to determine if MI is present.

2. Do you remember this patient? A 34 yom who was admitted with a syncopal attack.

4. Brugada syndrome Persistent STE in V1-V3 RBBB pattern THERE IS NO MI

5. A 81 yof CC : RLQ abdominal pain for 2-3 days. She also have nausea, vomiting No chest pain or S.O.B. Have MI 5 years ago

7. What is your Dx ? Does she have AMI?

8. Answer : NSTEMI! This is confirm by troponin elevation

9. “ It is important to recognize that BBB is present, because LBBB prevents any further interpretation of cardiogram, and RBBB can make interpretation difficult.” The ECG Made Easy by John R. Hampton

10. “ IMPORTANT: With LBBB, infarct cannot be accurately diagnosed on EKG.” Rapid Interpretation of EKG’s by Dale Dubin M.D.

11. So what is the problem now? BBB have signs that cover up/mask the signs of infarction

12. Let’s revise back the characteristics of BBB or intraventricular conduction delay (IVCD).

13. RABBIT hiding under RICE CAKE showing its RABBIT EARS

14. RBBB hiding under Right Leads showing its ‘ M’ pattern M Right Leads RBBB

15. RBBB LBBB “ M” “ W” “ W” “ M” Right lead Left lead Right lead Left lead III, aVF V1, V2 I, aVL V5, V6 III, aVF, V1, V2 I, aVL, V5, V6 Splitting of S2 Reversed Splitting of S2

16. Anymore signs for BBB?

17. How to name the waves in QRS complex? What is Q-wave? What is R-wave? What is S-wave? What is terminal deflection?

18. Q-R- S

19. R- S

20. Q- R

21. R-S- R ’ or “ M”

22. Q or QS

23. Let’s improve our vocabulary! Concordance Agreement, concord. Discordance Disagreement, discord.

26. T–inversion (Discordance with terminal deflection) ST –displacement from isoelectric line (Discordance with terminal deflection) P/S: But this is NO ST-displacement in RBBB

29. Normal BBB should obey this “normal condition”

30. So when BBB don’t obey this “normal condition” there is MI !

31. SGARBOSSA’s CRITERIA by Elena B. Sgarbossa

32. Modified* Sgarbossa’s Criteria Concordant STE > 1 mm 2. Concordant STD > 1 mm in V1, V2, or V3 3. Discordant STE > 5mm *Discordant STE > ¼ QRS

35. Now let’s put what we learn into practice!

36. 1

37. 2

38. 3

39. Now let’s make it harder. Try to determine the presence of MI and also it’s location.

40. 4

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42. The patient is an elderly female with a known history of LBBB who presented to the emergency ward with S.O.B.

43. 6

44. She did in fact rule in for a myocardial infarction with a CK of 700 and 21% MB fraction.

45. To use the rules of concordance in determination of the presence of MI seems easy, but not as easy as we think.

46. Final Case Middle-aged man admitted with recent chest pain. ECG with the attachment.

47. 7 Hint: There are 7 abnormalities

48. 1. Borderline STC 2. LBBB 3. 2° AV block (5:4 & 4:3 patterns) 4. Single PVC 5. Acute/evolving infero-lateral MI 6. Borderline low QRS voltage 7. Left atrial abnormality.

49. Cardiac cath. in this patient revealed severe 3 vessel coronary disease with evidence of thrombus in the right posterolateral branch. Left ventriculography showed a reduced left ventricle ejection fraction of 32% with inf./post. & apical/lat. wall motion abnormalities.

50. Additional comments: Mobitz type I (AV Wenckebach) block is not uncommon with acute inferior MI. Usually this condition disturbance is transient with inferior MI and does not require temporary or permanent pacing.

51. A Word of Caution NB! This criteria is useful, but final diagnosis of MI should always be confirmed by CE elevation and angiography (if possible).

52. Thank you for your attention!

54. Elevated troponin levels have been documented in other disease states and situations that are not associated with atherosclerotic epicardial coronary artery disease, including the following: * Pacing, automated implantable cardioverter-defibrillator * Tachyarrhythmias * Hypertension * Myocarditis * Myocardial contusion * Acute and chronic congestive heart failure * Cardiac surgery * Renal failure * Pulmonary embolism * Subarachnoid hemorrhage * Sepsis * Hypothyroidism * Shock