2. Bio-Med 350 Complications of Acute M.I. Douglas Burtt, M.D.

3. Bio-Med 350 Coronary atherosclerosis

4. Bio-Med 350 Schematic of an Unstable Plaque

5. Bio-Med 350 Cross section of a complicated plaque

6. Bio-Med 350 Journey down a coronary…

7. Bio-Med 350 Frank Netter: View of the Heart

8. Bio-Med 350 Left Anterior Descending Occlusion Occlusion of the left anterior descending coronary artery

9. Bio-Med 350 Experimental Data Canine studies – transient artery clamping or ligation Balloon angioplasty studies Time dependent series of events Chest Pain as a late event

10. Bio-Med 350 ACUTE M.I. THE “ISCHEMIC CASCADE” Chest pressure, etc. Localized systolic dysfunction Diastolic dysfunction Release of CPK Ischemic EKG changes Acute MI

11. Bio-Med 350 ACUTE M.I. THE “ISCHEMIC CASCADE” 1. Diastolic dysfunction 2. Localized systolic dysfunction 3. Ischemic EKG changes 4. Chest pressure, etc. 5. Release of CPK

12. Bio-Med 350 Time course of cell death 20 - 40 minutes to irreversible cell injury ~ 24 hours to coagulation necrosis 5 - 7 days to “yellow softening” 1 - 4 weeks: ventricular “remodeling” 6 - 8 weeks: fibrosis completed

13. Bio-Med 350 Think Anatomically!! Left main coronary artery supplies two-thirds of the myocardium LAD supplies ~ 40% of the L.V., including apex, septum and anterior wall RCA supplies less L.V. myocardium, but all of the R.V. myocardium

14. Bio-Med 350 Blood supply of the septum

15. Bio-Med 350 Think Anatomically!!! LAD supplies most of the conduction system below the A-V node (i.e. the His-Purkinje system) RCA supplies most of the conduction system at or above the A-V node (i.e. the A-V node and, usually, the S-A node)

16. Bio-Med 350 Conduction System of the Heart

17. Bio-Med 350 Conduction System: detail

18. Bio-Med 350 ACUTE M.I. Anatomical correlates LAD occlusion causes extensive infarction associated with: LV failure High grade heart block Apical aneurysm formation Thrombo-embolic complications

19. Bio-Med 350 ACUTE M.I. Anatomical correlates RCA occlusion causes moderate infarction associated with: RV failure Bradyarrhythmias Occasional mechanical complications

20. Bio-Med 350 ACUTE M.I. Arrhythmias Sinus bradycardia Sinus tachycardia Atrial fibrillation PVCs / ventricular tachycardia /ventricular fibrillation Heart block

21. Bio-Med 350 Arrhythmias: Inferior M.I. Sinus bradycardia -- S.A. nodal artery and increased vagal tone Heart block -- A-V nodal artery 1st degree A-V block Wenckebach 2nd degree A-V block A-V dissociation Atrial fibrillation -- L.A. stretch Ventricular tachycardia / fibrillation -- via “re-entry” or increased automaticity

22. Bio-Med 350 Arrhythmias: Anterior M.I. Sinus tachycardia -- low stroke volume Heart block -- His-Purkinje system Left or Right Bundle branch block Complete Heart Block Ventricular tachycardia / fibrillation due to “re-entry” or increased automaticity

23. Bio-Med 350 ACUTE M.I. Hypotension Identify hemodynamic subset Distinguish decreased preload from decreased cardiac output Think about hemodynamic monitoring

24. Bio-Med 350 Hemodynamic subsets Starling curves to plot “preload” versus cardiac output Identification of high risk subgroups Definition of cardiogenic shock L.V.E.D.P. Cardiac Output

25. Bio-Med 350 L.V.E.D.P. Cardiac Index (L/min/m2) 4 31 2 Hemodynamic Subsets

26. Bio-Med 350 Acute M.I. Mechanical Complications ª Rupture of free wall Tamponade Pseudoaneurysm ª Rupture of papillary muscle Acute Mitral regurgitation ª Rupture of intraventricular septum Acute V.S.D.

27. Bio-Med 350 ACUTE M.I. Papillary Muscle Rupture Leading to Acute M.R.

28. Bio-Med 350 ACUTE M.I. Papillary Muscle Rupture Leading to Acute M.R. Systolic murmur Giant V - waves on PC Wedge tracing Echo/Doppler confirmation RX with Afterload reduction Intra-aortic balloon pump

29. Bio-Med 350 “Flail” Mitral Leaflet

30. Bio-Med 350 Echo/Color Doppler of Acute M.R. LA LV RA

31. Bio-Med 350 Development of giant “V waves” P. A. pressure V-wave P.C. Wedge pressure

32. Bio-Med 350 Acute Mitral Regurgitation: Treatment Rapid diagnosis Afterload reduction Inotropic support Intra-aortic balloon pump Surgical valve replacement

33. Bio-Med 350 ACUTE M.I. Acute Ventricular Septal Defect Can occur with either anterior or inferior MICan occur with either anterior or inferior MI Peak incidence on days 3-7Peak incidence on days 3-7 Causes an abrupt left- to-right “shunt”Causes an abrupt left- to-right “shunt”

34. Bio-Med 350 ACUTE M.I. Acute Ventricular Septal Defect Abrupt onset of a harsh systolic murmur, often with a “thrill”Abrupt onset of a harsh systolic murmur, often with a “thrill” Detected by an oxygen saturation “step-up”Detected by an oxygen saturation “step-up”

35. Bio-Med 350 Oxygen saturation “step-up”

36. Bio-Med 350 Acute V.S.D.: Treatment Rapid diagnosis Afterload reduction Inotropic support Intra-aortic balloon pump Surgical repair of ruptured septum

37. Bio-Med 350 Intra-Aortic Balloon Pump Augments coronary blood flow during diastole Decreases afterload during systole by deflating at the onset of systole Reduces myocardial ischemia by both mechanisms

38. Bio-Med 350 Intra aortic balloon pump

39. Bio-Med 350 Intra-aortic balloon pump

40. Bio-Med 350 Free Wall Rupture Cardiac Tamponade Equalization of diastolic pressures Hypotension J.V.D. Clear lung fields Pulsus paradoxus Pseudoaneurysm Enlarged cardiac silhouette Echocardiographic diagnosis

41. Bio-Med 350 ACUTE M.I. Apical Aneurysm Associated with large, transmural antero-apical MI Can lead to LV apical thrombus Is associated with ventricular arrhythmias

42. Bio-Med 350 ACUTE M.I. Apical Aneurysm Causes “dyskinesis” of the apex Can be detected by cardiac echo Can lead to systemic emboli Anticoagulants may prevent embolization

43. Bio-Med 350 Right Heart Failure  Very commonly a sequela of Left Heart Failure  LVEDP  PCW  PA pressure  Right heart pressure overload  Cardiac causes  Pulmonic valve stenosis  RV infarction  Parenchymal pulmonary causes  COPD  ILD  Pulmonary vascular disease  Pulmonary embolism  Primary Pulmonary hypertension

44. Bio-Med 350 ACUTE M.I. Right Ventricular Infarction Jugular venous distention with clear lungs Equalization of right atrial and PCW pressures ST elevation in right precordial leads Therapy with fluids

45. Bio-Med 350 L.V.E.D.P. Cardiac Index (L/min/m2) 4 31 2 Hemodynamic Subsets

46. Bio-Med 350 ACUTE M.I. Pericarditis Pleuritic chest pain Radiation to the trapezius ridge Fever Pericardial friction rub

47. Bio-Med 350 ACUTE M.I. CARDIOGENIC SHOCK Large area of myocardial necrosis Consider mechanical complications Exclude correctable causes -- i.e. hypovolemia or R.V. infarct I.A.B.P. C.A.B.G. OR P.T.C.A.

48. Bio-Med 350

50. Summary Think anatomically!!! LAD vs. RCA Think hemodynamic subsets!!! Watch for mechanical complications

51. Bio-Med 350 THE END