Heart Diseases – Anatomy, Types, Symptoms & Causes
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.
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
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.
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.
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.
2. Irregular Heartbeats (Arrhythmias)
Abnormal heart rhythms such as:
- Too fast (Tachycardia)
- Too slow (Bradycardia)
- Irregular rhythm
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.
4. Cardiomyopathy (Heart Muscle Disease)
Disease that weakens heart muscles, making pumping difficult.
Types:
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy
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
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
2. Arrhythmia Symptoms
- Palpitations / fluttering
- Dizziness
- Fainting (Syncope)
- Racing heartbeat
- Slow heartbeat
- Chest discomfort
- Shortness of breath
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
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
Causes (Aetiology)
1. Coronary Artery Disease
- Atherosclerosis
- Poor diet
- Obesity
- Smoking
- Physical inactivity
2. Arrhythmias
- Cardiomyopathy
- CAD
- Diabetes
- Alcohol/caffeine excess
- Stress
- Hypertension
- Drug misuse
- Medications
- Valve disease
3. Congenital Defects
- Genetic factors
- Maternal illness
- Medications during pregnancy
4. Cardiomyopathy Causes
Dilated:
- Genetic inheritance
- Heart attacks
- Infections
- Toxins
- Cancer drugs
Hypertrophic:
- Usually inherited
Restrictive:
- Amyloidosis
- Connective tissue disorders
- Unknown causes
5. Endocarditis (Heart Infection)
Caused by:
- Bacteria
- Viruses
- Parasites
6. Valve Disease Causes
- Congenital defects
- Rheumatic fever
- Infections
- Connective tissue disorders
Risk Factors
- Increasing age
- Male gender (higher early risk)
- Family history
- Smoking
- High BP
- High cholesterol
- Diabetes
- Obesity
- Sedentary lifestyle
- Stress
- Poor dental hygiene
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
