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Pathophysiology of Myocardial Infarction

ON on modifiable

Factor/Predisposing factors- Age- Gender (male)-Genetics abnormalities

Modifiable Factors: Precipitating

Factors

-Diet (high fat and high - Stresscarbohydrates)- Hyperlipoproteinemia - Postmenopausal estrogen- Hypertension

defficiency- Sedentary lifestyle - Type A personality

Increase accumulation/deposition of

blood cholesterol and fibrous tissue in

Endothelial Injury/

-Monocyte/lymphocyte adhesion andemigration- LDL & HDL imbalance-Smooth muscle cell migration to theintima.

Plaque remodeling- progressive

formation and development of

- macrophages and t-lymphocytes

activation of proteolytic enzymes

( cytokines & metalloproteases) w/in the

Disruption of the atheromatous plaque by

proteolytic enzymes>degradation of ECM

of the plaques fibrous cap> (Rupture,

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Activation of coagulation/ clotting cascade1.platelet adhesion2.platelet activation3.platelet aggregation

Promotes thrombus

Embolus

Coronary arterial occlusion

-Anterior descending

branch of left coronary

artery

Right coronary artery

-posterior/ inferior wall

infarction

Circumflex branch of left

coronary artery-lateral wall infarction(15-

Decreased blood supply to

the myocardium

Decreased oxygen supply to

the myocardium

Anaerobic glycolysis

Increase production of lactic acid

Decreased blood ph

concentration>

Signs and

symptoms

-fatigue

-palpitation

-sweating-weakness

-tachycardia

-nausea

-vomiting

Chest pain/ chest

tightness

-stabbing

-crushing-burning

-squeezingPrimary somatosensory

cortexMyocardial

necrosis

Stimulation of sympathetic

nervous system

Impair Myocardial

enzymatic and

metabolic activity

Decreased

Stroke volume

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Decreased Decreased

cardiac

vascul

Increased Increase

d heart

Increased

Stroke

Increased

Venous

Decreased

Diastolic

Decreased

Cardiac

Inadequate

tissue

erfusion

Decreasedvolume to met

metabolic needs

of the bod

Increased

Cardiac

Hypoxia

Irreversible MI

>20minutes after

onset of MI

Complete infarc-

large area/size of

myocardial

Reversible MI