General Anatomy & Physiology of the Heart

• The human heart is divided into four chambers:
  • Two upper chambers — atria
  • Two lower chambers — ventricles
• The right side of the heart pumps oxygen-poor blood to the lungs through the pulmonary arteries.
• In the lungs, blood receives oxygen and returns to the left side of the heart via the pulmonary veins.
• The left side then pumps oxygen-rich blood to the entire body through the aorta.

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Heart Valves

There are four main valves that regulate blood flow:

• Aortic valve
• Mitral valve
• Pulmonary valve
• Tricuspid valve

Functions:

• Open only when required
• Allow one-way blood flow
• Close tightly to prevent leakage

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Heartbeats (Cardiac Cycle)

The heart works in a continuous cycle:

• Systole (Contraction):
  Ventricles contract and pump blood to the lungs and body.
• Diastole (Relaxation):
  Ventricles relax and fill with blood from the atria.

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Electrical System of the Heart

• The heartbeat is controlled by electrical signals.
• Signals originate in the right atrium.
• They travel through specialized pathways to the ventricles.
• This coordinated signaling ensures proper pumping and oxygen exchange.

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5 Major Types of Heart Diseases

1. Blood Vessel Disease – Coronary Artery Disease (CAD / IHD)

Damage or blockage in coronary arteries reduces blood supply to the heart.

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2. Irregular Heartbeats (Arrhythmias)

Abnormal heart rhythms such as:

• Too fast (Tachycardia)
• Too slow (Bradycardia)
• Irregular rhythm

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3. Congenital Heart Defects

Heart abnormalities present at birth.

Common Types:

Patent Ductus Arteriosus (PDA)

• Fetal blood vessel fails to close after birth.

Patent Foramen Ovale (PFO)

• Hole between atria that remains open after birth.

Coarctation of Aorta

• Narrowing of the aorta present from birth.

Tetralogy of Fallot (4 defects):

• Ventricular septal defect
• Pulmonary stenosis
• Displaced aorta
• Right ventricular hypertrophy

Cor Pulmonale

• Right-sided heart failure due to lung disease.

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4. Cardiomyopathy (Heart Muscle Disease)

Disease that weakens heart muscles, making pumping difficult.

Types:

• Dilated cardiomyopathy
• Hypertrophic cardiomyopathy
• Restrictive cardiomyopathy

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5. Valvular Heart Disease

Damage or dysfunction of heart valves.

Conditions:

• Stenosis: Narrow valve opening
• Prolapse: Valve slips out of place
• Regurgitation: Backward leakage of blood

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Symptoms of Heart Diseases

1. Coronary Artery Disease (CAD)

Due to Atherosclerosis (plaque buildup)

Symptoms:

• Chest pain (Angina)
• Chest tightness/pressure
• Shortness of breath
• Fatigue
• Nausea

Men: Typical chest pain
Women: Chest discomfort, fatigue

Other signs:

• Pain in neck, jaw, throat, back
• Limb numbness or coldness
• Risk of heart attack or stroke

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2. Arrhythmia Symptoms

• Palpitations / fluttering
• Dizziness
• Fainting (Syncope)
• Racing heartbeat
• Slow heartbeat
• Chest discomfort
• Shortness of breath

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3. Congenital Heart Defect Symptoms

In Children:

• Blue skin/lips (Cyanosis)
• Swelling (legs, abdomen, eyes)

In Infants:

• Breathlessness during feeding
• Poor weight gain

In Adults (mild defects):

• Easy fatigue
• Breathlessness on exertion
• Swollen hands/feet

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4. Valvular Disease Symptoms

• Chest pain
• Fainting
• Fatigue
• Irregular heartbeat
• Breathlessness
• Swollen ankles/feet

If due to Endocarditis:

• Fever
• Persistent cough
• Skin rashes
• Weakness
• Heartbeat changes

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Causes (Aetiology)

1. Coronary Artery Disease

• Atherosclerosis
• Poor diet
• Obesity
• Smoking
• Physical inactivity

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2. Arrhythmias

• Cardiomyopathy
• CAD
• Diabetes
• Alcohol/caffeine excess
• Stress
• Hypertension
• Drug misuse
• Medications
• Valve disease

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3. Congenital Defects

• Genetic factors
• Maternal illness
• Medications during pregnancy

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4. Cardiomyopathy Causes

Dilated:

• Genetic inheritance
• Heart attacks
• Infections
• Toxins
• Cancer drugs

Hypertrophic:

• Usually inherited

Restrictive:

• Amyloidosis
• Connective tissue disorders
• Unknown causes

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5. Endocarditis (Heart Infection)

Caused by:

• Bacteria
• Viruses
• Parasites

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6. Valve Disease Causes

• Congenital defects
• Rheumatic fever
• Infections
• Connective tissue disorders

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Risk Factors

• Increasing age
• Male gender (higher early risk)
• Family history
• Smoking
• High BP
• High cholesterol
• Diabetes
• Obesity
• Sedentary lifestyle
• Stress
• Poor dental hygiene

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Complications of Heart Disease

• Heart failure
• Heart attack
• Stroke
• Blood clots
• Aneurysm (rupture → internal bleeding)
• Peripheral artery disease
• Claudication (leg pain while walking)
• Sudden cardiac arrest