2.16 Stages of Cardiovascular Disease Development

Cardiovascular diseases develop progressively over time. The main stages include angina pectoris, heart attack, and heart failure. Each stage represents a worsening of the underlying condition, usually atherosclerosis.

Definition

Angina Pectoris: Angina pectoris is occasional chest pain that occurs when the heart muscle does not receive enough oxygen. It is most likely to occur when the heart is working hard due to physical or emotional stress.

Heart Attack (Myocardial Infarction): A heart attack occurs when a blood clot completely blocks a coronary artery, or atherosclerosis reaches a critical level, causing massive damage to the heart muscle.

Heart Failure: Congestive heart failure is the inability of the heart to pump all the blood coming to it. The cardiac output is unable to keep pace with the venous return.

Main Idea

• Atherosclerosis — plaque builds up in arteries
• Angina pectoris — chest pain due to reduced blood flow
• Heart attack — complete blockage; muscle death
• Heart failure — heart cannot pump enough blood

Each stage is more serious than the previous one.

Core Concept

• Angina pectoris = chest pain; warning sign
• Heart attack = myocardial infarction; muscle death
• Heart failure = pump failure; blood backs up
• Atherosclerosis = underlying cause
• Scar tissue = forms after heart attack
• Cardiac muscle = does not divide
• Cardiac output = cannot keep pace with venous return

Detailed Explanation

Angina Pectoris

• Due to atherosclerosis, a person may feel occasional chest pain.
• Angina is most likely to occur when the heart is labouring hard because of physical or emotional stress.

• Angina is a signal that part of the heart is not receiving a sufficient supply of oxygen.
• It indicates that a heart attack could occur in the future.

• Occasional chest pain
• Pain during physical or emotional stress

Heart Attack (Myocardial Infarction)

• Many heart attacks occur without warning.
• A blood clot may completely block a coronary artery.
• Atherosclerosis may reach a critical level causing massive damage to the heart muscle.

• Sudden heavy squeezing ache or discomfort in the centre of the chest.
• Pain may radiate to shoulder, arm, neck, or jaw.
• Sweating
• Nausea
• Shortness of breath
• Dizziness or fainting

• The whole process is called myocardial infarction (heart muscle death due to lack of oxygen).
• When heart muscles die, they are not replaced because cardiac muscles do not divide.
• When a person survives a heart attack, scar tissue (a type of connective tissue) grows into the areas where the heart muscles have died.
• The scar tissue cannot contract as cardiac muscle.
• As a result, the damaged heart is permanently weakened.

Heart Failure

• Congestive heart failure is the inability of the heart to pump all the blood coming to it.
• The cardiac output is unable to keep pace with the venous return.

• Blood backs up in the veins.
• Organs do not receive enough blood.
• Fluid accumulates in tissues (edema).

Congenital Heart Problem

• Congenital heart problems result from abnormalities in the embryonic development.
• It can be related to the malfunctioning of cardiac valves e.g., valvular stenosis.

• Valvular stenosis
• Septal defects
• Tetralogy of Fallot

Intermediate Level

Stages of Cardiovascular Disease

Comparison of Angina and Heart Attack

Heart Failure

Congenital Heart Problems

Formula / Mathematical Form

Not applicable to this topic.

Solved Example

Not applicable to this topic (descriptive topic).

Important Points

• 1. Cardiovascular disease develops in stages.
• 2. Atherosclerosis is the underlying cause.
• 3. Angina pectoris is chest pain due to reduced blood flow.
• 4. Angina is a warning sign of heart attack.
• 5. Heart attack is myocardial infarction.
• 6. Heart attack causes muscle death.
• 7. Cardiac muscle does not divide.
• 8. Scar tissue forms after heart attack.
• 9. Scar tissue cannot contract.
• 10. Heart failure is inability to pump enough blood.
• 11. Cardiac output cannot keep pace with venous return.
• 12. Congenital heart problems are present at birth.
• 13. Valvular stenosis is a congenital heart problem.
• 14. Early detection can prevent progression.
• 15. Lifestyle changes can help.

Remember

• - Angina = chest pain; warning sign
• - Heart attack = myocardial infarction
• - Heart failure = pump failure
• - Atherosclerosis = underlying cause
• - Scar tissue = forms after heart attack
• - Cardiac muscle = does not divide
• - Cardiac output = cannot keep pace with venous return
• - Congenital = present at birth
• - Valvular stenosis = congenital heart problem

Common Mistakes

• 1. Confusing angina and heart attack — Angina is chest pain; heart attack is muscle death.
• 2. Thinking angina causes permanent damage — Angina does not cause permanent damage.
• 3. Forgetting that cardiac muscle does not divide — This is why scar tissue forms.
• 4. Mixing up the stages — Atherosclerosis → angina → heart attack → heart failure.
• 5. Believing heart failure means the heart stops — Heart failure means the heart cannot pump enough blood.
• 6. Confusing congenital with acquired — Congenital means present at birth.
• 7. Thinking valvular stenosis is acquired — It can be congenital.
• 8. Forgetting the role of scar tissue — Scar tissue cannot contract.
• 9. Mixing up the symptoms — Angina: occasional chest pain; heart attack: severe, persistent pain.
• 10. Thinking heart failure only affects older people — It can affect younger people too.

Quick Revision

Cardiovascular disease develops in stages. Atherosclerosis is the underlying cause, with plaque buildup in arteries. Angina pectoris is chest pain due to reduced blood flow; it is a warning sign of a heart attack. A heart attack (myocardial infarction) occurs when a blood clot completely blocks a coronary artery, causing muscle death. Cardiac muscle does not divide, so scar tissue forms, permanently weakening the heart. Heart failure is the inability of the heart to pump all the blood coming to it; cardiac output cannot keep pace with venous return. Congenital heart problems result from abnormalities in embryonic development, such as valvular stenosis. Early detection and lifestyle changes can help prevent progression.

60-Second Revision

• Angina = chest pain; warning sign
• Heart attack = myocardial infarction
• Heart failure = pump failure
• Atherosclerosis = underlying cause
• Scar tissue = forms after heart attack
• Cardiac muscle = does not divide
• Cardiac output = cannot keep pace with venous return
• Congenital = present at birth
• Valvular stenosis = congenital heart problem
• Warning: Cardiac muscle does not divide; scar tissue cannot contract

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• Chapter:
• 2. Blood Circulatory System of Man

• Topic:
• 2.17 DIAGNOSIS OF CARDIOVASCULAR DISORDERS

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