Download MBBS Myocardial Infarction Lecture PPT

Download MBBS (Bachelor of Medicine and Bachelor of Surgery) Latest Myocardial Infarction Lecture PPT


MYOCARDIAL

INFARCTION.

Myocardial infarction ( MI ),
or acute myocardial infarction ( AMI ).
commonly known as a heart

attack, occurs when blood flow decreases or stops to a part

of the heart, causing damage to the heart muscle.

Most common symptom is chest pain or discomfort which

may travel to the shoulder, arm, back , neck or jaw. Often it

occurs in centre or left side of the chest and last for more

than a few minutes.

other symptom may include shortness of breath, nausea,

feeling faint, feeling tired.
CHEST PAIN(MI).
WHAT is heart attack ?

Occurs when the coronary arteries that supply the

heart muscle become blocked.

Partially blocked is called angina.

When fully blocked it causes a myocardial infarction or a

heart attack.
CAD.

Ischemic heart disease( IHD) or coronary artery

disease(CAD) :

Heart attack:
A heart attack occurs when

the blood flow to a part of the heart is blocked by a

blood clot. If this clot cuts off the blood flow

completely , the part of the heart muscle supplied by

that artery begins to die.


MI.

Myocardial infarction(MI) is a disease condition

which is caused by reduced blood flow in a coronary

artery due to atherosclerosis and occlusion of an

artery by an embolus or thrombus.

Most myocardial infarction occur due to coronary

artery disease.

The complete blockage of a coronary artery caused by

a rupture of an atherosclerotic plaque.


Blockage of coronary artery.
COMPLICATION OF MI.

About 30% of people have atypical symptoms.

Women more often have atypical symptoms than men.

An MI may cause : -

Heart failure, an irregular heart beat, cardiogenic

shock, or cardiac arrest.
Symptom angina/mi.
RISK FACTORS.

Unchangeable risk factor :--

Age- the older you get, the greater the

chance.

Sex----males have a greater rate aven after women pass

menopause.

Family history---if family members have had CHD, there is

a greater chance.
Changeable risk factors.

Hypertension
Serum cholesterol
Obesity
Diabetes mellitus
Physical inactivity
Cigarette smoking
Alcohol intake
CHOLESTEROL.

Waxy fat substance in the blood.
Liver makes all the cholesterol it need to survive,

other source of cholesterol come from food.

GOOD CHOLESTEROL---
HDL---it does not tendency to clog

arteries.

Level should be > 35.
Cholesterol.

LDL--
bad cholesterol.
Tendency to increase risk of CHD.
Major component of the atherosclerotic plaque that

clogs arteries.

Levels should be < 130.
DIABETES.

2-4 fold risk for CHD.
Asymptomatic CHD~ 30-40 %.
Painless AMI,arrythmias, CCF.
CHD- A major ( 60% ) cause of mortality.

PHYSICAL INACTIVITY--

Increasing physical activity has been shown to decrease

blood pressure.

Moderate to increase physical activity for 30-45 minutes on

most days of the week is recomended.
SMOKING.

SMOKING-
Contribute to development of atherosclerosis.
Lowers levels of HDL.
Female smokers have a higher risk than male smokers.

ALCOHOL not too good either!
Alcohol kills brain cells
Damage liver
Increases BP
Increases risk of heart attack.


PATHOPHYSIOLOGY.

Coronary artery cannot supply enough blood to the heart in

response to the demand due to CAD.

|
Within 10 seconds myocardial cells experience ischemia.
|
Ischemic cells cannot get enough oxygen or glucose.
|
Cells convert to anaerobic metabolism, and produces Lactic as

waste---Pain develops from lactic acid accumulation.

|
Patient feels anginal symptoms until receiving demand

increeases O2 requirements of myocardial cells.




RISK OF HIGH CHOLESTEROL.
Criteria of MI.

Troponin or CK-MB increased with one of these:

Chest pain
Positive ischemic change in ECG( ST segment elevation and

T wave changes )

Pathological Q wave presence in ECG Newly.
MI DIAGNOSIS.

WHO CRITERIA.

History of ischemic type of chest discomfort.
Evolutionary ECG changes.
Rise and fall in serum cardiac marker.

LAB.DIAG :

Best marker: Troponins.
Next test : CK-MB.

Predictive

CRP > 3mg/L( highest risk).
CLINICAL DIAGNOSIS OF MI.

Silent MI-
in diabetes mellitus, elderly, cardiac transplantation

recipients.

Typical features-
profuse sweating, dyspnea, chest pain,

rapid, weak pulse etc.
TESTES USEFUL FOR DIAGNOSIS OF MI.

1.Electrocardiograms(ECG).
2.Blood tests.
3.Coronary angiography.(CAG).

An ECG which is a recording of the heart's electrical

activity, may confirm an elevation MI(STEMI), if ST

elevation is present.

Commonly used blood test include troponin and less

often creatne kinase MB.
STEMI.
CARDIACBIOMARKERS.

Cardiac biomarkers are used to detect cardiac

diseases.

Acute coronary syndrome resulting from myocardial

ischemia.

Congestive heart failure.

CARDIAC MARKERS TESTED IN

ACUTE CHEST PAIN

UNSTABLE ANGINA

SUSPICIOUS ECG CHANGES

HISTORY SUGGESTIVE OF MYOCARDIAL

INFARCTION.


CARDIAC MARKERS.

A. CARDIAC MARKERS FOR ACUTE CORONARY SYNDROME
1.CREATINE KINASE (CK-MB )
2.CARDIAC TROPONINS ( cTnT )
3.HIGH SENSITYVITY TROPONIN
4.BNP and NTproBNP
B. RISK MARKER FOR CARDIAC DISEASE (PREDICTION)
1.PLASMA hsCRP
2.TOTAL CHOLESTEROL LEVEL IN SERUM
3.LDL- CHOLESTEROL and Apo-B100 level
4.HDL level and ApoA1 level
5.Lp(a) level
6.Serum homocysteine level
ELECTROCARDIOGRAM.


ACUTE ANTERIOR MI.
MI-Management.
MEDICAL management MI.

This post was last modified on 30 November 2021