Myocardial_Infarction.pdf cardiovascular

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1. CHAPTER-I
MYOCARDIAL INFARCTION

2. Definition ƒ
Amyocardialinfarction,morecommonlyknownasMIor
acute myocardial infarction (AMI) or heart attack is a
condition where there is interruption of blood supply to a
partoftheheart

6. PATHOPHYSIOLOGY

12. Clinical Presentation
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P
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J
,
,
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S
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Nausea,


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S
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H
and/or
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A
(more
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U
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G
ƒ
N A
S

13. DIAGNOSIS
PhysicalExamination:
Pallor, diaphoresis, tachycardia, S4, dyskinetic cardiac impulse may be
present. If CHF exists, rales and S3 are present. Jugular venous
distentioniscommoninrightventricuqlarinfarction.
ECG : ST elevation, followed by T-wave inversion, then Q-wave development
overseveralhours
Non-STElevationMI,orNSTEMISTdepressionfollowedbypersistentST-Twave
changes
withoutQ-wavedevelopment.
Cardiac Biomarkers Cardiac-specifictroponins T and I are highly specific for
myocardialinjuryandarethepreferre dbiochemicalmarkersfordiagnosis
ofMI

14. C
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Heart failure
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Ventricular fibrillation

15. R
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High Blood Cholesterol (Hyperlipidemia).
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Diabetes (Diabetes Mellitus).
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Male Gender
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Family History of Heart Disease.
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High Blood Pressure (Hypertension).
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Smoking or tobacco use

16. TREATMENT

17. Nonpharmacologicaltreatment ƒ
Keep  your  blood pressure, blood sugar, and 
cholesterol  under  control.
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Don't smoke.
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Eat a heart‐healthy diet rich in fruits, vegetables, 
and whole grains,  and low in animal fat.
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Get plenty of exercise, at least 30 minutes  a day, at 
least 5 days a week.
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Getcheckedandtreatedfordepression.
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Limityourself to no more than  one drink  a day for 
women,  and no more than  two drinks a day for men.
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Stay at a healthy weight.  Aim for a body mass  index  
(BMI) of between 18.5 and 24.9.

18. Antiplateletand antithrombotic therapy
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Aspirin 
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Clopidogrel
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Ticlopidine
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Unfractionedheparin
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Low molecular weight heparin à
(e.g. enoxaparin
, dalteparin
, tinzaparin
)
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GPIIb/IIIainhibitors

20. Fibrinolytic therapy ƒ
Streptokinase  
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Alteplase
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Reteplase
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Tenecteplase

21. Analgesics ƒ
Morphine sulfate IV
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Nitroglycerine

22. Beta blockers ƒ
Propranolol
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Metaprolol
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Atenolol

23. Other therapies ƒ
ACE inhibitors
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Calcium channel blockers
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Amiodarone
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Lidocaine

24. Antiplatelets
Aspirinhasanantiplatelet
effectwhichinhibitsformation
offurtherthrombi
(bloodclots)thatclogarteries.
Anantiplatelet drug(antiaggregant) is a member of a
class ofpharmaceuticals
that decreaseplatelet
aggregation
andinhibitthrombus
formation.

27. Heparin
ƒ
Heparin binds to the enzyme inhibitor antithrombin
III (AT). The activated AT
then inactivatesthrombin
and other proteases involved in blood clotting, most
notablyfactor Xa
. The rate of inactivation of these proteases by AT can
increase by up to 1000-fold due to the binding of heparin
ƒ
It produces its major anticoagulant effect by inactivating thrombin and
activated factor X (factor Xa) through an antithrombin (AT)-dependent
mechanism. Heparin binds to AT through a high-affinity pentasaccharide,
which is present on about a third of heparin molecules. For inhibition of
thrombin, heparin must bind to both the coagulation enzyme and AT, whereas
binding to the enzyme is not required for inhibition of factor Xa.

28. GPIIb/IIIa antagonists
ƒ
GPIIb/IIIaantagonists. à
Platelet GPIIb/IIIainhibitors block the final pathway of
platelet aggregation

29. Fibrinolytic agent
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Improve myocardial oxygen supply by dissolving coronary
thrombus, reestablishing blood flow to ischemic myocardium.
Prompttherapy limitsinfarct sizeand improvessurvival

30. Morphine sulphate
ƒ
Reduce myocardial oxygen demand By causing pheripheral
arterial dilatation that decrease systemic vasularresistance and
afterload, circulating concentration of catecholamine

31. Nitroglycerin
Nitroglycerin
under the tongue or buccally can be given is useful to
alleviatechest pain
. The Glyceryl Trinitrate acts as a nitric oxide
donor to smooth muscles cells adjacent to the coronary artery
endothelium resulting in increased vasodilation and increased
coronarybloodflow.

32. Beta blockers
β-blockers decrease the effect of the sympathetic nervous system on the
heart. Since it is known that the sympathetic nervous system increases the
heart rate and blood pressure in order to increase the cardiac output.
Hence its blockage spares the heart the extra work load.

33. EMERGENCY TREATMENTS ƒ
Angioplasty
is a procedure to open narrowed or blocked blood vessels
that supply blood to the heart. Usually a small, metal mesh tube called
a stent is placed at the same time.
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Angioplasty is often the first choice of treatment. It should be done
within 90 minutes after you get to the hospital, and no later than 12
hours after a heart attack.

34. ƒ
A stent is a small, metal mesh tube that opens up (expands)
inside a coronary artery. A stent is often placed after
angioplasty. It helps prevent the artery from closing up again.
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Some patients may also have heart bypass surgery to open
narrowed or blocked blood vessels that supply blood to the
heart. This procedure is also called open heart surgery
.