Angina pectoris & Myocardial infarction - B. Pharma 2nd Semester Pathophysiology notes pdf

Angina pectoris & MI


       Angina pectoris

       Myocardial infarction


At the end of this PDF Notes, student will be able to

        Explain the etiology involved angina pectoris

        Describe the etiology involved in myocardial infarction

        Discuss the pathogenesis of angina pectoris and myocardial infarction

        Describe the complications associated with angina pectoris and Myocardial infarction

Angina pectoris

       Discomfort due to transient myocardial ischemia

       Heart muscle does not receive enough blood (nutrient & O2) resulting in chest pain

Etiology of Angina Pectoris

       Atherosclerosis of large coronary arteries

       Heart valve disease

       Thickening of heart muscles

       Coronary artery spasm


Symptoms of Angina Pectoris

       Gripping of central chest pain

       ↑ shortness of breath on exercise

       Sense of heaviness or numbness in the arm, shoulder, elbow or hand usually on the left side

       Constricting sensation in the throat

       Mild ache to severe pain

       Sweating and fear

Pathogenesis and types of Angina

       Imbalance between myocardial oxygen demand and supply

Stable/ Typical/ Exertional/ Classical Angina

       Provoked by physical exertion

       Heaviness, squeezing and sensation of constriction in the chest

       Pain subsides on resting

       Depression in ST segment of ECG

       No elevation in the blood enzyme level if no myocardial injury

Variant/ Prinzmetal Angina

       Pain at rest

       No relationship with physical activity

       Occur due to coronary artery spasm

       Spasm – due to release of vasoconstrictor by mast cells in coronary artery

       Attacks are painful, occur between midnight & daily morning

       ST segment elevation in ECG

       Patient respond well to vasodilator like nitroglycerine

Unstable/ Atypical/ Cresendo/ Preinfarction Angina or Acute coronary insufficiency

       Frequent onset of pain for longer duration

       Occurs often at rest

       Indication of myocardial infarction

Microvascular angina

       Chest pain , no apparent coronary artery damage

       Poor functioning of blood vessels  of heart, arm or legs

       May occur during exercise or at rest


Myocardial infarction

       Myocardial infarction / Heart attack results from complete obstruction to blood flow in coronary artery

       Imbalance in supply and demand of O2 to myocardium

       Underlining cause – coronary artery disease

Symptoms of myocardial infarction

       Severe chest pain


       Chest pain radiating through jaw, shoulder, arms and back

       Epigastric discomfort with or without nausea/ vomiting

       Sproathy and blood stained sputum

       Dizziness, weakness, Anxiety

       Irregular heart beat

       Heart burn & indigestion

Etio-pathogenesis of Myocardial infarction

Atherosclerotic causes

       Accounts for 75% of cases

       Fatty streak deposits on the coronary artery

       Endothelium develop into an atherosclerotic plague depending on the presence of risk factors

       Risk factors – HT, DM, Smoking, Hyperlipidemia

       Plaque progression, proliferation and disruption of integrity of blood vessel

       Results in narrowing off coronary artery & MI

Non atherosclerotic causes

       Accounts for 10% of the causes of MI

       Coronary vasospasm

       Inflammation of arteries

       Coronary embolism

       Development of thrombosis


Complications of Myocardial infarction

       Cardiac arrhythmia

       Congestive heart failure

       Cardiogenic shock

       Rapture of heart

       Mural thrombosis



       Angina is the discomfort due to transient myocardial ischemia where heart muscle does not receive enough blood (nutrient & O2) resulting in chest pain

       Myocardial infarction / Heart attack results from complete obstruction to blood flow in coronary artery

       Causes of angina and MI  include Atherosclerosis of large coronary arteries, heart valve disease, thickening of heart muscles, coronary artery spasm, hypertension

       Occurs mainly due to the imbalance in supply and demand of O2 to myocardium

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