CARDIOVASCULAR SYSTEM

 CARDIOVASCULAR SYSTEM

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1. ANATOMY OF THE CARDIOVASCULAR SYSTEM

Importance:

✔ The cardiovascular system is crucial for oxygen delivery, waste removal, homeostasis, and immune response.
✔ Understanding anatomy is essential for diagnosing cardiac conditions, interpreting ECG, and performing invasive procedures like catheterization.

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1.1 OVERVIEW OF THE CARDIOVASCULAR SYSTEM

✔ Divisions:

• Heart → Pumps blood through the circulatory system.
• Blood vessels → Arteries, veins, capillaries transport blood.
• Blood → Carries nutrients, oxygen, and immune cells.

✔ Circulatory Loops:

• Pulmonary Circulation → Carries deoxygenated blood from the right heart to lungs and returns oxygenated blood.
• Systemic Circulation → Delivers oxygen-rich blood from the left heart to body tissues and returns deoxygenated blood.

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1.2 ANATOMY OF THE HEART

✔ Location & External Features

• Position: In mediastinum, slightly left of midline.
• Layers of Heart:
  • Pericardium → Fibrous & serous layers.
  • Myocardium → Thickest layer, contains cardiac muscle.
  • Endocardium → Inner lining of heart chambers.

✔ Heart Chambers & Valves

• Right Atrium (RA) → Receives deoxygenated blood from SVC, IVC, and coronary sinus.
• Right Ventricle (RV) → Pumps blood to lungs via pulmonary artery.
• Left Atrium (LA) → Receives oxygenated blood from pulmonary veins.
• Left Ventricle (LV) → Pumps blood to body via aorta.

✔ Heart Valves:

• Atrioventricular Valves → Tricuspid (RA-RV) & Mitral/Bicuspid (LA-LV).
• Semilunar Valves → Pulmonary (RV → Pulmonary Artery) & Aortic (LV → Aorta).

✔ Coronary Circulation (Blood Supply of the Heart)

• Right Coronary Artery (RCA) → Supplies right atrium, SA node, AV node, inferior heart.
• Left Coronary Artery (LCA) → Divides into:
  • Left Anterior Descending (LAD) → Supplies anterior LV, septum.
  • Left Circumflex (LCx) → Supplies lateral LV.
• Venous Drainage → Coronary sinus → Right atrium.

✔ Cardiac Conduction System

• SA Node (Pacemaker, 60-100 bpm) → Generates impulse.
• AV Node (40-60 bpm) → Delays impulse for ventricular filling.
• Bundle of His → Right & Left Bundle Branches → Conduct impulse to ventricles.
• Purkinje Fibers (15-40 bpm) → Initiates ventricular contraction.

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1.3 BLOOD VESSELS & HEMODYNAMICS

✔ Types of Blood Vessels

• Arteries → Carry oxygenated blood (except pulmonary arteries).
• Arterioles → Major resistance vessels, regulate blood pressure.
• Capillaries → Site of exchange between blood and tissues.
• Veins → Carry deoxygenated blood (except pulmonary veins).
• Venules → Smallest veins, drain capillary beds.

✔ Layers of Blood Vessels

• Tunica Intima → Inner endothelial layer.
• Tunica Media → Smooth muscle (thicker in arteries).
• Tunica Externa → Connective tissue layer.

✔ Major Arteries & Veins

• Aorta → Largest artery, branches into systemic arteries.
• Superior & Inferior Vena Cava → Return deoxygenated blood to right atrium.
• Pulmonary Artery & Vein → Link heart and lungs.
• Portal Circulation → Liver receives blood via hepatic portal vein.

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2. PHYSIOLOGY OF THE CARDIOVASCULAR SYSTEM

Importance:

✔ Essential for cardiac function, blood flow regulation, oxygen delivery, and homeostasis.
✔ Disorders like heart failure, shock, and arrhythmias arise due to altered physiology.

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2.1 CARDIAC CYCLE

✔ Phases:

• Atrial Systole → Atria contract, push blood into ventricles.
• Isovolumetric Contraction → Ventricles contract, AV valves close.
• Ventricular Ejection → Semilunar valves open, blood enters arteries.
• Isovolumetric Relaxation → Ventricles relax, semilunar valves close.
• Ventricular Filling → AV valves open, blood enters ventricles.

✔ Heart Sounds:

• S1 ("Lub") → Closure of AV valves.
• S2 ("Dub") → Closure of semilunar valves.
• S3 & S4 → Abnormal, indicate heart failure.

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2.2 BLOOD PRESSURE REGULATION

✔ Mean Arterial Pressure (MAP) = CO × TPR
✔ Factors Affecting BP:

• Cardiac Output (CO) = HR × SV
• Total Peripheral Resistance (TPR)
• Baroreceptors (Carotid sinus, Aortic arch) → Detect BP changes.
• Renin-Angiotensin-Aldosterone System (RAAS) → Increases BP.
• Atrial Natriuretic Peptide (ANP) → Lowers BP.

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3. PATHOLOGY OF THE CARDIOVASCULAR SYSTEM

Importance:

✔ Understanding cardiac pathologies helps in early diagnosis & targeted treatment.
✔ Diseases like CAD, MI, valvular diseases, arrhythmias are leading causes of morbidity & mortality.

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3.1 COMMON CARDIOVASCULAR DISEASES

✔ Hypertension (HTN) → BP >140/90 mmHg.
✔ Coronary Artery Disease (CAD) → Atherosclerosis of coronary arteries.
✔ Myocardial Infarction (MI) → Cardiac muscle necrosis due to ischemia.
✔ Heart Failure (HF) → Inability of heart to pump blood adequately.
✔ Arrhythmias → Abnormal heart rhythms (AF, VF, VT, AV Blocks).
✔ Valvular Heart Disease → Stenosis or regurgitation (AS, MS, MR).

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CLINICAL EXAMINATION OF THE CARDIOVASCULAR SYSTEM

IMPORTANCE OF CLINICAL EXAMINATION

✔ The cardiovascular system (CVS) is evaluated to detect cardiac diseases early, assess severity, and guide management.
✔ A systematic approach covering inspection, palpation, percussion, and auscultation is crucial for accurate diagnosis.
✔ Common conditions diagnosed via clinical examination:

• Hypertension (HTN)
• Valvular heart diseases (stenosis, regurgitation)
• Coronary artery disease (CAD)
• Heart failure (HF)
• Arrhythmias

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1. GENERAL EXAMINATION IN CVS

✔ Before examining the heart, a general examination helps identify systemic manifestations of cardiac diseases.
✔ Components:

1.1 APPEARANCE OF THE PATIENT

✔ Dyspnea at rest? → CHF, Pulmonary edema.
✔ Pallor? → Anemia, infective endocarditis.
✔ Cyanosis?

• Central cyanosis → Congenital heart disease, Eisenmenger syndrome.
• Peripheral cyanosis → Heart failure, shock.
  ✔ Edema?
• Pitting edema → Right heart failure.
• Anasarca → Severe CHF, nephrotic syndrome.

1.2 BLOOD PRESSURE MEASUREMENT

✔ Measure in both arms → Significant difference (>20 mmHg) suggests aortic dissection.
✔ Wide pulse pressure (>60 mmHg)? → Aortic regurgitation, high-output states.
✔ Narrow pulse pressure (<25 mmHg)? → Pericardial tamponade, cardiogenic shock.

1.3 PULSE EXAMINATION

✔ Radial Pulse:

• Rate? (Normal: 60-100 bpm)
• Rhythm? (Regular or Irregular—AF, PVCs)
• Volume? (Bounding → AR, weak → shock)
• Character? (Collapsing pulse → AR, Pulsus Paradoxus → Cardiac tamponade)

✔ Other Pulses:

• Carotid pulse: Best for assessing aortic stenosis & regurgitation.
• Brachial pulse: Useful in infants.
• Femoral pulse: Delayed in coarctation of aorta.
• Dorsalis pedis/posterior tibial pulses absent? → Peripheral artery disease.

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2. PRECORDIAL EXAMINATION (EXAMINATION OF THE CHEST WALL & HEART)

✔ Systematic approach → Inspection, Palpation, Percussion, Auscultation

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2.1 INSPECTION (Look for visible cardiac signs on the chest wall.)

✔ Chest deformities?

• Pectus excavatum/carinatum → Associated with Marfan’s syndrome.
• Visible apex beat? → Normally seen in the 5th ICS, midclavicular line.
• Displaced apex beat? → LVH (left), RVH (right).

✔ Jugular Venous Pressure (JVP)

• Raised JVP? → CHF, pericardial tamponade, tricuspid regurgitation.
• Cannon A waves? → Complete heart block.
• Absent A waves? → Atrial fibrillation.

✔ Visible pulsations in suprasternal notch? → Aneurysm of aortic arch.

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2.2 PALPATION (Assess cardiac motion, thrills, and heaves.)

✔ Apex Beat Palpation:

• Location: Normally 5th ICS, midclavicular line.
• Displacement:
  • Leftward → LVH (HTN, AR, MR).
  • Rightward → RVH (COPD, pulmonary HTN).
• Sustained heaving impulse? → LV hypertrophy (Aortic stenosis, HTN).
• Tapping apex beat? → Mitral stenosis.
• Diffuse, hyperdynamic apex? → Aortic regurgitation, fever, hyperthyroidism.

✔ Parasternal Heave → Indicates Right Ventricular Hypertrophy (RVH).

✔ Thrills (Palpable Murmurs)

• Aortic Stenosis → Thrill in right 2nd ICS.
• Mitral Stenosis → Thrill in apex.

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2.3 PERCUSSION (Less commonly used but still relevant in some cases.)

✔ Helps in assessing cardiac enlargement.
✔ Cardiac dullness shifting? → Pericardial effusion.

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2.4 AUSCULTATION (HEART SOUNDS & MURMURS)

✔ S1 (First Heart Sound)

• Loud S1? → Mitral stenosis.
• Soft S1? → Mitral regurgitation.

✔ S2 (Second Heart Sound)

• Loud A2? → Hypertension.
• Fixed splitting of S2? → Atrial septal defect (ASD).
• Paradoxical splitting? → Aortic stenosis, LBBB.

✔ Extra Heart Sounds:

• S3 (Ventricular gallop) → Early diastolic filling sound (Heart failure).
• S4 (Atrial gallop) → Late diastolic filling sound (LVH, HTN, Aortic stenosis).

✔ Murmurs (High-Yield for Exams & Clinical Practice)

✔ Murmurs (High-Yield for Exams & Clinical Practice)

Systolic Murmurs:

• Aortic Stenosis (AS) → Crescendo-decrescendo murmur, best heard in right 2nd ICS, radiating to carotids.
• Mitral Regurgitation (MR) → Holosystolic murmur, best heard at apex, radiates to axilla.
• Pulmonary Stenosis (PS) → Ejection systolic murmur, best heard in left 2nd ICS, radiates to back.
• Ventricular Septal Defect (VSD) → Harsh holosystolic murmur, best heard in left lower sternal border.

Diastolic Murmurs:

• Aortic Regurgitation (AR) → Early diastolic decrescendo murmur, best heard at left sternal border.
• Mitral Stenosis (MS) → Low-pitched rumbling mid-diastolic murmur, best heard at apex with bell in left lateral position.

Continuous Murmurs:

• Patent Ductus Arteriosus (PDA) → Machine-like murmur, best heard at left infraclavicular area.

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3. ADDITIONAL CVS EXAMINATIONS

3.1 PERIPHERAL SIGNS OF CARDIOVASCULAR DISEASES

✔ Clubbing → Infective endocarditis, congenital cyanotic heart disease.
✔ Splinter hemorrhages, Osler’s nodes, Janeway lesions → Infective endocarditis.
✔ Xanthelasma, corneal arcus → Hyperlipidemia.

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3.2 SPECIAL TESTS IN CARDIOVASCULAR EXAMINATION

✔ Valsalva Maneuver:

• Increases hypertrophic cardiomyopathy murmur.
• Decreases aortic stenosis murmur.

✔ Handgrip Test:

• Increases regurgitant murmurs (MR, AR).
• Decreases stenotic murmurs (AS, HOCM).

✔ Squatting Test:

• Increases AS, MR, VSD murmurs.
• Decreases HOCM murmur.

✔ Standing or Amyl Nitrate Administration:

• Increases HOCM murmur.
• Decreases AS murmur.

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4. CLINICAL INTERPRETATION & DIFFERENTIAL DIAGNOSIS

✔ Differentiating Left vs. Right Heart Failure:

Left-Sided Heart Failure (LHF)

• Dyspnea on exertion
• Orthopnea (difficulty breathing while lying flat)
• Paroxysmal nocturnal dyspnea (PND)
• Pulmonary edema (crackles at lung bases, pink frothy sputum)
• S3 gallop (ventricular overload)
• Cardiomegaly on chest X-ray

Right-Sided Heart Failure (RHF)

• Peripheral edema (pitting edema in lower limbs)
• Hepatomegaly & ascites (congestive hepatopathy)
• Jugular venous distension (JVD) with positive hepatojugular reflux
• Nocturia (due to fluid redistribution when supine)
• Right ventricular heave (suggesting right ventricular hypertrophy)

✔ Combined heart failure → Biventricular failure with features of both LHF & RHF.

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5. DIFFERENTIATION OF COMMON CARDIAC CONDITIONS

Aortic Stenosis vs. Hypertrophic Cardiomyopathy (HOCM)

✔ Aortic Stenosis (AS)

• Ejection systolic murmur, crescendo-decrescendo
• Best heard in right 2nd ICS, radiates to carotids
• Decreases with Valsalva, increases with squatting

✔ Hypertrophic Obstructive Cardiomyopathy (HOCM)

• Ejection systolic murmur, but increases with Valsalva
• Best heard in left sternal border, no carotid radiation
• Sudden cardiac death risk in young athletes

Mitral Stenosis vs. Mitral Regurgitation

✔ Mitral Stenosis (MS)

• Low-pitched, diastolic rumbling murmur at apex
• Loud S1, opening snap after S2
• Seen in rheumatic heart disease

✔ Mitral Regurgitation (MR)

• Pansystolic (holosystolic) murmur at apex
• Soft S1, often radiates to axilla
• Causes: Rheumatic heart disease, infective endocarditis, MVP

Aortic Regurgitation vs. Mitral Stenosis

✔ Aortic Regurgitation (AR)

• Early diastolic murmur, decrescendo
• Best heard in left sternal border
• Bounding pulses, wide pulse pressure

✔ Mitral Stenosis (MS)

• Mid-diastolic rumbling murmur, best heard at apex
• Low-pitched with opening snap

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6. INTEGRATING CLINICAL FINDINGS WITH DIAGNOSTIC TESTS

6.1 INVESTIGATIONS TO CONFIRM CVS DIAGNOSIS

✔ Electrocardiogram (ECG)

• ST-elevation myocardial infarction (STEMI) → ST elevation in leads corresponding to infarct area
• Non-ST elevation MI (NSTEMI)/Unstable Angina → ST depression, T wave inversion
• Left Ventricular Hypertrophy (LVH) → Tall R waves in V5-V6, deep S waves in V1-V2
• Right Ventricular Hypertrophy (RVH) → Tall R wave in V1, right axis deviation
• Atrial fibrillation (AF) → No P waves, irregularly irregular rhythm
• Bundle Branch Blocks:
  • LBBB (Left Bundle Branch Block) → Broad QRS, deep S in V1, notched R in V6
  • RBBB (Right Bundle Branch Block) → Broad QRS, RsR’ pattern in V1

✔ Echocardiography (ECHO)

• Gold standard for valvular heart diseases (stenosis, regurgitation)
• Left ventricular ejection fraction (LVEF) assessment for heart failure
• Hypertrophic Cardiomyopathy (HOCM) → Asymmetrical septal hypertrophy
• Dilated Cardiomyopathy (DCM) → Enlarged LV with reduced ejection fraction
• Pericardial Effusion/Tamponade → Fluid around the heart, swinging heart motion

✔ Chest X-ray (CXR)

• Cardiomegaly → Enlarged cardiac silhouette (Cardiothoracic ratio >50%)
• Pulmonary edema → Kerley B lines, bat-wing pattern, perihilar haze
• Aortic dissection → Widened mediastinum
• Pericardial effusion → "Water bottle" heart shape

✔ Cardiac Biomarkers (Blood Tests)

• Troponin I/T → Elevated in MI, best marker for myocardial injury
• CK-MB (Creatine Kinase-MB) → Rises in MI but falls faster

• BNP (Brain Natriuretic Peptide) & NT-proBNP → Elevated in heart failure (useful for differentiating cardiac vs. pulmonary dyspnea).
• D-dimer → Elevated in pulmonary embolism, DVT, or DIC.

✔ Coronary Angiography

• Gold standard for diagnosing coronary artery disease (CAD).
• Detects stenosis, occlusion, and collateral circulation.

✔ Cardiac MRI

• Best for myocarditis, cardiomyopathies, cardiac masses, and pericardial diseases.
• Helps in assessing myocardial viability in ischemic heart disease.

✔ Holter Monitoring (24-hour ECG)

• Useful for diagnosing paroxysmal arrhythmias, atrial fibrillation, and unexplained syncope.

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7. VASCULAR EXAMINATION

7.1 ARTERIAL EXAMINATION

✔ Pulse Examination

• Rate: Normal (60–100 bpm), tachycardia (>100 bpm), bradycardia (<60 bpm)
• Rhythm: Regular vs. irregular (e.g., Atrial fibrillation – irregularly irregular pulse)
• Volume & Character:
  • Bounding pulse → Aortic regurgitation, hyperthyroidism, fever
  • Thready pulse → Cardiogenic shock, severe hypovolemia
  • Pulsus paradoxus → >10 mmHg drop in BP during inspiration (seen in cardiac tamponade, severe asthma, COPD)
  • Pulsus alternans → Alternating strong and weak beats (left ventricular failure)
  • Anacrotic pulse → Slow-rising, best felt in aortic stenosis
  • Bisferiens pulse (double peak) → Aortic regurgitation, HOCM

✔ Peripheral Arterial Disease (PAD) Signs

• Pallor, cold extremities, ulcers (ischemic ulcers), gangrene
• Buerger’s Test: Raise legs to 45° → Pallor; Lower → Rubor (suggests arterial insufficiency)
• Ankle-Brachial Index (ABI):
  • <0.9 → Suggests PAD
  • <0.5 → Critical limb ischemia

✔ Aneurysm Examination

• Abdominal Aortic Aneurysm (AAA): Pulsatile mass in epigastrium
• Popliteal Aneurysm: Expansile mass behind the knee

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7.2 VENOUS EXAMINATION

✔ Chronic Venous Insufficiency (CVI) Features

• Varicose veins → Dilated, tortuous veins (usually saphenous system)
• Edema → Pitting type, worsens with prolonged standing
• Skin changes → Hyperpigmentation, lipodermatosclerosis (thick, woody skin)
• Venous ulcers → Medial malleolus, shallow with granulation tissue

✔ Tests for Varicose Veins

• Trendelenburg Test: Checks valve incompetence in saphenous vein
• Perthe’s Test: Assesses deep venous patency
• Brodie-Trendelenburg Test: Differentiates between deep and superficial venous incompetence

✔ Deep Vein Thrombosis (DVT) Signs

• Calf tenderness, swelling, warmth, erythema
• Homan’s Sign → Pain on dorsiflexion of the foot (not very reliable)
• Moses Sign → Pain on squeezing calf from sides
• Wells Score → Clinical probability of DVT

✔ Investigation for Venous Disorders

• Doppler Ultrasound → First-line for DVT & varicose veins
• Venography → Gold standard for deep vein thrombosis (rarely used)
• D-dimer Test → High sensitivity, but low specificity for DVT/PE

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