Definition
• Otherwise know as Myocardial Infarction
• An MI occurs when there is a diminished blood supply to
the heart which leads to myocardial cell damage and
ischemia.
• Contractile function stops in the necrotic areas of the
heart.
• Ischemia usually occurs due to blockage of the coronary
vessels.
• This blockage is often the result of thrombus that is
superimposed
on
an
ulcerated
or
unstable
atherosclerotic plaque formation in the coronary artery
Coronary Artery Anatomy
Risk Factors
• The presence of any risk factor is associated with
doubling the risk of an MI.
Non Modifiable
Age
Gender
Family history
Pathophysiology
• Atherosclerosis with superimposed coronary thrombosis
• Slowly growing high-grade stenoses can progress to complete
occlusion but do not usually precipitate acute MI d/t collateral
circulation
• During development of plaques, abrupt transition can occur,
resulting in
• Platelet activation
• Thrombin generation
• Thrombus formation
• Blood flow occlusion leads to imbalance between supply and
demand and could lead to myocardial necrosis
• Less severe stenosis with lipid-laden plaques and fragile caps
more likely to rupture and causing thrombsis and MI
Pathophysiology
Stable Angina
• Progressive
narrowing of
coronary lumen
• Stable fibrous cap
Unstable
Angina
• Progressive
narrowing
• Acute worsening
of coronary
lumen due to
thrombus
formation
NSTEMI
• Acute worsening
of coronary lumen
due to thrombus
formation
• Sub-occlusive/
transient coronary
thrombus with
myocardial necrosis
STEMI
• Minimal prior
narrowing of
coronary lumen
• Acute rupture of
thin fibrous cap
• Occlusive
thrombus
formation
• Acute injury
pattern
• Myocardial
necrosis
Signs and Symptoms
•
•
•
•
Chest pain
Nausea and vomiting
Sympathetic
nervous
system
stimulation: cold sweat, temperature
increase
Cardiovascular changes
• Initially the BP and pulse may be
elevated.
• Later, BP will drop due to
decreased cardiac output.
• Urine output will decrease
• Lung sounds will change to
crackles
• Jugular
veins
may become
distended and have obvious
pulsations.
Long Term Care
• Modern treatments, along with healthy lifestyle choices, can assist
in recovering from a heart attack and greatly reduce the risk of
further heart problems and relieve or control symptoms such as
angina.
• The most important things you can do to reduce your risk and aid
heart attack recovery are:
• Aspirin, Beta Blockers and Clopidogrel will be indefinite.
• Lipid lowering medication along with diet modifications.
• Smoking cessation
• Lifestyle modifications (physically active, achieve and maintain a
healthy body weight )
• Control blood pressure
• If the person affected has diabetes, they should also aim to keep
their blood glucose levels within the normal non-diabetic range.