IHD + MI Flashcards
IHD highest cause
Atherosclerosis
Pathogenesis of IHD [3]
Reduced blood flow
- Occlusion by atheroma, acute plague rupture, thrombosis
Increased Demand - hypertrophy of myocardium, exercise, pregnancy, hyperthyroid
Decreased pO2 content
- anaemia, CO poisioning, lung disease, left to right shunts
Unstable vs Stable plagues
Stable plagues larger - thicker fibrous cap than lipid core
Cx of Ischemic Heart Disease [4]
Angina
MI
Chronic IHD, HF
Sudden death by arrhythmia without infraction
Angina definition
Chest pain on exertion due to ischemia of myocardium
Stable vs Unstable angina + cause
Fixed level of exertion vs increasing frequency of triggers w lower activity;
Unstable due to disruption of plague - thrombosis
Prinzmental Angina
Arterial spasms
What is MI
Death of myocardium;
Coronary Arteries and regions supplied [4]
LAD: Antero-SEPTAL of left ventricle
LCA: Antero-Lateral left ventricle
LCX: Lateral
RCA: Posterior
Clinical Diagnosis of MI
Clinical - chest pain
ECG
Serum elevated cardiac enzymes
- myoglobin; CKMB, creatine kinase myocardial band, Troponin
Myoglobin is a small protein found in heart and skeletal muscles that binds oxygen
Progression
Gross + Histology
0.5 1 1-3 3-10 1.5-2 mths
Half a day: not visible TTC stain
1 Day: Pale, blotched discoloration
1-3 Days: Pale, Yellow
3-10 days: Hyperaemic
1 Day:
Eosinophilic infracted Muscle, No nuclei, Intercellular Oedema
1-3 Days:
Neutrophils
3-10 days:
Granulation Tissue, angiogenesis, fibroblasts
1.5-2 months: Scar, Hypertrophy
Cx of MI on heart anatomy
Ventricles
- LVFailure, Congestive HF
- Myocardium rupture (3-5 days near necrotic myocardium) - cardiac tamponade, blood in pericardial sac, increases pressure on atrium, affect blood filling
- tamponade due to TRANSMURAL infraction of myocardium, leading to blood entering sac
- fibrosis, decreased elasticity, aneurysm
- thrombosis
Conduction - arrhythmia - cardiac death
- fibrosis is arrhythmogenic
Valves
- ruptured papillary muscles leading to valvular dysfunction; Valves to Chordae Tendineae to Papillary M
Pericarditis
Pathophysiology of Chronic IHD
Chronic atherosclerotic narrowing of CA, slow loss of myocardial fibers leading to insidious cardiac failure and death
MI - HF
Two ways ischemia leads to sudden cardiac death
Ischemia - Infraction - Fibrosis - Arrhythmia - Sudden Death
Ischemia - Arrhythmia - Sudden Death, VF from acute plague change, stenosis
What does LAD supply
left anterior descending artery
Antero-septal
