Ischemic Heart Disease
Ischemia
DemandSupply
Cause of Myocardial ischemia in
90% cases is
Atherosclerosis in
Coronaries
Clinical manifestations of IHD
It’s a spectrum
MI : Most severe ischemia
Angina pectoris : Ischemia Less ischemia
Chronic IHD
Sudden cardiac death
Ischemic Heart
Disease
Atherosclerosis in Coronaries
Atherosclerosis
Lifestyle
Obstructive lesion of 75% or greater causes symptomatic ischemia induced by exercise90% Obstruction can cause Symptoms at rest
Atherosclerosis
Acute MI
Sudden Cardiac Death
Acute Plaque change
Acute Plaque changes
Rupture
Erosion
Hemorrhage
Vulnerable Plaques
Plaques containing :
Large foam cells
High Lipid content
Thin Fibrous cap
Inflammatory cells
Angina pectoris
Attacks of substernal / precordial
chest discomfort causes by transient
myocardial ischemia that falls short
of infarction
Constricting
Squeezing
Knifelike
Patterns of Angina pectoris
1. Stable / Typical
2. Prinzmetal / Variant
3. Unstable / Crescendo
Myocardial Infarction
Heart Attack
Myocardial infarction – Death of cardiac
muscles due to ischemia
Transmural Infarcts – Involving full thickness
Of ventricular wall
Subendocardial infarcs – Involving inner
1/3 area of ventricular wall.
Males > Females
(till menopause)
Risk factors :
Pathogenesis
Sudden change in the Plaque
Adhesion of platelets to the exposed part
Platelets release : Thromboxane A2,
serotonin and Platelet factor 3 , 4
Vasospasm
Stimulation of Coagulation pathway
Thrombus blocks the coronary artery
90%
In 10% cases
Vasospasm
Emboli
?? Unexplained
Effects of MI on the Heart
End of Aerobic glycolysis
Start of Anaerobic glycolysis
Lactic acid accumulation
Ischemia for 20 – 40 mins :
Irreversible damage to myocytes
Coagulation Necrosis is the Mechanism
of cell Death of Myocytes …
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