Disorders of Cardiovascular System

DISORDERS OF CARDIOVASCULAR SYSTEM

1. Heart (Cardiac) Failure

Heart failure occurs when the heart is unable to pump sufficient blood to meet the metabolic needs of the body.

Heart failure may affect:

• Left side of the heart
• Right side of the heart

Because both sides are part of a single circuit, failure of one side often leads to failure of the other.

Left ventricular failure is more common due to the higher workload of the left ventricle.

2. Ischaemic Heart Disease

Ischaemic heart disease (IHD) is also called:

• Coronary artery disease (CAD)
• Coronary heart disease (CHD)

It occurs when blood supply to the heart muscle is reduced or obstructed, usually due to atherosclerosis of coronary arteries.

Reduced oxygen supply leads to:

• Angina pectoris
• Myocardial infarction

a) Angina Pectoris

Angina is often called angina of effort.

It occurs when increased cardiac output during:

• Physical exertion
• Cold exposure
• Emotional stress

causes severe chest pain that may radiate to:

• Arms
• Neck
• Jaw

b) Myocardial Infarction (MI)

Myocardial infarction, commonly known as a heart attack, occurs when blood flow to part of the heart muscle is blocked.

• Usually caused by a blood clot in a coronary artery
• Leads to tissue damage or death

iii) Rheumatic Heart Disease

Rheumatic fever is an inflammatory disease that may follow streptococcal throat infection, especially in children and young adults.

It is an autoimmune disorder, where antibodies damage:

• Heart
• Joints
• Skin

Although death is rare in the acute phase, permanent damage to heart valves may develop later, leading to disability and cardiac failure.

iv) Infective Endocarditis

Infective endocarditis is inflammation of the endocardium and heart valves.

• Common causative agents: bacteria (most common), fungi
• Predisposing factors include:
• Bacteraemia
• Depressed immunity
• Pre-existing heart abnormalities

v) Cardiac Arrhythmias

Cardiac arrhythmias are disorders of heart rate or rhythm caused by abnormal impulse generation or conduction.

Normal sinus rhythm:

• Rate: 60–100 beats per minute

Disruption of electrical activity leads to arrhythmias.

• Atrial fibrillation: rapid, uncoordinated atrial contraction
• Ventricular fibrillation: life-threatening emergency

In ventricular fibrillation:

• Effective pumping stops
• Pulse is absent
• Consciousness is lost
• Death occurs if untreated

vi) Congenital Abnormalities

Congenital abnormalities are structural defects present at birth.

• About 3% of newborns have major malformations
• Cause 20–25% of perinatal deaths
• Major causes of childhood illness and disability

Common congenital disorders include:

• Heart defects
• Neural tube defects
• Down syndrome

Summary Table: Major Cardiovascular Disorders