1. Anatomy
    2. 1. Mediastinum
    2. The Heart Development
    3. Pericardium
    4. Features of the Heart
    5. Arterial Supply of Heart
    6. Venous Drainage of the Heart
    7. Conducting System of Heart
    8. Nervous System of Heart
    9. Foetal Circulation and Changes at Birth
    10. Microscopic Structure of Heart
    11. Arteries
    12. Arch of Aorta
    13. Descending Thoracic Artery
    14. Abdominal Aorta
    15. Subclavian Artery
    16. Axiallary Artery
    17. Internal Thoracic Artery
    18. Brachial Artery
    19. Radial Artery
    20. Ulnar Artery
    21. Palmar Arches
    22. External Iliac Artery
    23. Internal Iliac Artery
    24. Femoral Artery
    25. Popliteal Artery
    26. Posterior Tibial Artery
    27. Anterior Tibial Artery
    28. Dorsalis Pedia Artery
    29. Common Carotid Artery
    30. External Carotid Artery
    31. Internal Carotid Artery
    32. Veins
    33. Internal Jugular Vein
    34. External Jugular Vein
    35. Superior Venacava
    36. Inferior Venacava
    37. Brachiocephali vein
    38. Subclavian vein
    39. Axillary vein
    40. Cephalic vein
    41. Basilic vein
    42. Azygous vein
    43. Hemiazyous vein
    44. Accessory Hemiazyoug Vein
    45. Internal Hemiazygous Vein
    46. Internal Iliac Vein
    47. Femoral Vein
    48. Popliteal Vein
    49. Long Saphenous Vein
    50. Small or Short Saphenous Vein
    51. Hepato-portal System
    52. Lymphatic System
    53. Spleen
    54. Thymus
    55. Thoracic duct
  2. Pharmacology
    3. 56. Congestive Heart Failure
    57. Therapy of Arrhythmiasis
    58. Angina pectoris
    59. Therapy of Hypertension
    60. Therapy of Shock
    61. Haemostatic Agents
    62. Therapy of Thromboembolic Disorder
    63. Thrombolytic or Fibrinolytics
    64. Antifibrinolytics
    65. Antiplatelet Drugs
    66. Therapy of Iron Deficiency Anemia
    67. Therapy of Megaloblastic Anaemia
    68. Hypolipidemic Drugs and Plasma Expanders
  3. Physiology
    4. 69. Properties of Myocardial Cells
    70. Heart - A Mechanical Pump
    71. Cardiac Cycle
    72. Electrocardiogram (ECG)
    73. Cardiac Output (CO)
    74. Haemodynamics of Circulation
    75. Heart Sounds
    76. Arterial Pulse
    77. Blood pressure
    78. Regional circulation
    79. Cardiovascular chanes during exercise
    80. Edema Dropsy of fluid retention
    81. Shock
    82. Hematology
  4. Pathology
    5. 83. Anaemia
    84. Hypertension
    85. Hypertensive Heart Disease
    86. Ischemic Heart Disease
    87. Angina pectoris
    88. Myocardial infarction
    89. Rheumatic Fever and Rheumatic Heart Disease (RHD)
    90. Acute Pericarditis
    91. Myocarditis
    92. Infective Endocarditis (IE)
    93. Congenital Heart Disease
    94. Cardiomyopathies
    95. Arteriosclerosis
    96. Atherosclerosis
    97. Inflammatory Disease of Blood Vessels
    98. Aneurysms and Dissection
    99. Congestive Heart Failure
    100. Iron Deficiency Anaemia
    101. Megaloblastic anaemia
    102. Pancytopenia
    103. Leucocytosis and Leucopenia
    104. Aplastic anaemia
    105. Haemolytic anaemia
    106. Hereditary Spherocytosis
    107. Haemoglobinipathies
    108. Thalassemia syndrome
    109. Sickle Cell Disease
    110. Leukaemia
    111. Leukemoid reaction
    112. Lymphadenitits
    113. Hodgkin lymphoma
    114. Non-hodgkin lymphoma
    115. Myeloproliferative disorders
    116. Myelofibrosis
    117. Multiple myeloma
    118. Bleeding disorders
    119. Coagulation disorders
    120. any
    121. Blood grouping
  5. Microbiology
    6. 122. Introduction of Blood borne infections
    123. Infective Endocarditis
    124. Brucella
    125. Rickettsiae
    126. Leishmania donovani
    127. Plasmodium
    128. Wuchereria bancrofti
  6. Biochemistry
    7. 129. Metabolism in Blood Cells
    130. Iron metabolism
    131. Haemoglobin
    132. Lipoprotein metabolism
    133. Biochemical aspect of MI
Pathology
88. Myocardial infarction

1.

List the risk factors of myocardial infarction.

[2071]

➤

2.

Describe morphological changes in myocardial infarction.

[2070, 3077]

➤

3.

Write short notes on: Complications of myocardial infarction.

[2077]

➤

4.

Define myocardial infarction. Describe the etiology of myocardial infarction and its microscopic features.

(8)

[2059]

➤

5.

Describe the etiopathogenesis and gross and microscopic features of myocardial infarction.

(8)

[2056, 2052]

➤

6.

Write the predisposing factors of ischemic heart disease. List the complications of myocardial infarction.

(4)

[1053]

➤

7.

Describe the morphological changes in acute myocardial infarction.

[1076]

➤

INTRODUCTION
  • •
    Myocardial infarction is the death of the cardiac tissue to prolonged severe ischemia.
  • •
    Severe ischemia lasting 20 to 30 minutes or longer leads to myocardial infarction.
    • ◉ Commonly involved vessels:
    1. Left anterior descending coronary artery (LAD) - 40-50%
    2. Right coronary artery (RCA) - 30-40%
    3. Left circumflex coronary artery (LCX)
PATHOGENESIS
graph TD 1["Sudden change in atheromatous plaque:<ul><li>Errosion or ulceration</li><li>Fissuring or rupture</li><li>Intraplaque hemorrhage</li></ul>"] 2["Exposure to sub-endocardial collagen and necrotic plaque contents"] 3["<ol><li>Platelet adherence</li><li>Release reaction</li><li>Platelet activation</li></ol>They aggregate to form microthrombi"] 4["Vasospasm due to mediators released from platelet"] 5["Activation of coagulation pathway, adding bulk to thrombus"] 6["Arterial occlusion"] 7["Severe ischemia"] 8["Loss of oxidative phosphorylation and decreased generation of ATP"] 9["Accumulation of potentially noxious metabolites; e.g., lactic acid"] 10["Loss of contractility"] 11["Severe ischaemia for 20 to 30 minutes or longer"] 12["Irreversible cell injury"] 13["Microvascular injury"] 14["Myocardial infarction"] 1 --> 2 2 --> 3 3 --> 4 4 --> 5 5 --> 6 6 --> 7 7 --> 8 8 --> 9 9 --> 10 10 --> 11 11 --> 12 12 --> 13 13 --> 14
MORPHOLOGY
Time
Gross
Microscope
0 - 1/2 hrs
-
-
1/2 - 4 hrs
-
-
4 - 12 hrs
Mottling
Early Coagulative necrosis
12 - 24 hrs
Mottling
Ongoing coagulative necrosis
1-3 days
Mottling border; Central yellow-tan infarct
Complete coagulation necrosis
3-7 days
Hyperemia border; Central yellow-tan softening
Early phagocytosis
7-10 days
Depressed red-tan border; Maximally central yellow tan softening
Complete phagocytosis
10-14 days
Depressed red-gray infarct border
Complete granulation
2 weeks - 2 mths
Scarring starts
Increased collagen deposition
> 2 mths
Scarring completes
Dense collagenous scar
COMPLICATIONS
  1. Contractile dysfunction
    1. Left ventricular failure
      • •
        Pump failure (cardiogenic shock) in 10% to 15% patients
    2. Right ventricular failure
      • •
        Pulmonary vascular congestion and
      • •
        Interstitial pulmonary transusate
  2. Arrhythmia
    1. Sinus bradycardia
    2. Heart block (Asystole)
    3. Tachycardia
    4. Ventricular fibrillation
  3. Myocardial rupture
    1. Hemopericardium and Cardiac tamponade
    2. Rupture of the ventricular septum → VSD and Left to right shunting
    3. Papillary muscle rupture
  4. Pericarditis
    1. Fibrinous or fibrohemorrhagic pericarditis (Dressler syndrome)
    2. Develops about the second or third day following a transmural infarct
  5. Chamber dilation
  6. Infarct expansion
  7. Mural embolism
  8. Ventricular aneurysm
  9. Papillary muscle dysfunction
  10. Progressive late heart failure

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