Cardiovascular Pathology

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 Atrial Septal Defect (ASD) • •

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Incomplete closure of the fossa ovalis Æ allowing inter-arterial communication Often a mild disease not detected until adult life o Due to pressure and volume handled by the atria level is lower compared to the systemic level Pulmonary flow is increased to about twice the systemic output Pressure (Left > Right) o o  blood preferentially goes from Left Æ Right atrium = ↑ Pulmonary blood flow RV is dilated and hypertrophied o Adaptation of the right ventricle to the ↑ workload(hypertrophy) Æ dilatation

Complication o o

o

Pulmonay HPN RV failure (due to dilatation)  death also from CHF (due to arrhythmia) and IHD Shunt reversal (Late cyanosis)  ↑ pressure from right side to left  Mixing of unoxygenated blood from right side to the left Æ to systemic circulation

Types: 1. Fossa or Ostium seccundum (most common) 2. Outlet (Primum SD) 3. Sinus Venosus defect 4. Coronary sinus defect

Fossa Ovalis

Right Atrium

 ASD

2 flaps of muscles should overlap to close to fossa

Left Atrium

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Ventricular Septal Defect (VSD) • •

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Most common cardiac anomaly in children (recognized early) incomplete closure of ventricular septum Æ left to right interventricular communication o inadequate growth or absent fusion of embryologic septal components Increases risk for infective endocarditis Functional disturbance depends on the size of the defect o ↑ defect = ↑ disturbance and vice versa Small defects can sometimes close spontaneously as the heart enlarges o st o Surgery (1 year) to prevent irreversible obstructive pulmonary vascular disease Large VSDs result in overload of both ventricles Similar to ASD (movement is from L Æ R) o o Right ventricle carries the initial burden

Complications Eisenmenger syndrome o Pulmonary HPN o shunt reversal cyanosis (Late cyanosis) o •

VSD

Supraventricularis Defect 

Muscle band

Muscle band

 Infraventricularis Defect 

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 Patent Ductus Arteriosus (PDA) • • •

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90% occur as isolated anomalies (common in babies whose mothers had rubella) Rough machine-like murmur (S4) on auscultation Permanent closure of the DA is usually complete by 8 weeks after birth o Patency due to failure to contract and become fibrotic in response to ↑ arterial oxygen Large caliber of the ductus Æ incomplete closure o should be closed as early in life as feasible

Complications o o o

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Pulmonary HPN Shunt reversal Cardiac hypertrophy  Adaptation to ↑ workload  eventually leads to heart failure Dilated pulmonary artery

 PDA

Left Pulmonary Artery Patent Ductus Arteriosus

Aorta take note of the 3 branches

Pulmonary Artery

Left Pulmonary Artery

Patent Ductus Arteriosus (w/ probe)

Aorta O ened

Pulmonary Artery (Opened)

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Tetralogy of Fallot • •

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Most common cyanotic congenital anomaly Four Components: o Large VSD Stenosis of pulmonary outflow tract o   Narrowing of the lumen due to subpulmonic muscle block  o Biventricular origin of the aorta (overrides the right ventricle)  septal defect is below overriding aorta  receives blood from the RV and LV Æ EARLY cyanosis o Right ventricular hypertrophy  0.6-1cm thick (normal – 0.5cm) results from anterosuperior & leftward displacement of the infundibular septum

Complications o o o o

Heart failure Polycythemia ↑ risk for thrombosis ↑ risk for infective endocarditis

Left to Right Shunt Tetralogy of Fallot

Initial LÆR Shunt VSD PDA ASD PTA

No Shunt Coartaction of the aorta Pulmonary stenosis Aortic stenosis

Stenosis VSD

RV hypertrophy

Aorta

Stenotic

VSD

RV hypertrophy

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 Pulmonary Hypertension in Congenital HD w/ Left and Right Shunts Grade I – Medial Hypertrophy (Reversible)

Tunica Adventitia External Elastic Membrane Tunica Intima Single layer of Endothelial cells (simple squamous) Internal Elastic Membrane Hypertrophied Tunica Media

Grade II – Intimal Hyperplasia (Reversible)

Internal Elastic Membrane

Intimal Hyperplasia External Elastic Membrane Hypertrophied Tunica Media

Grade III – Intimal Fibrosis (Irreversible)

Fibrous tissue in the Tunica Intima (Occlusion of the lumen)

Hypertrophied Tunica Media

Grade IV – Plexiform Lesions (Irreversible)

Fibrous Tissue

 Newly formed Capillaries

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 Rheumatic Heart Disease • •

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cardiac involvement in rheumatic fever  Rheumatic Fever: immunologic hypersensitivity rxn to Strep antigens (NO BACTERIA present) o Ig & complement demonstrable in myocardial fiber membrane Cross reacting Ab against Strep protein and myocardial sarcolemma in patient’s sera o  Ab w/c supposedly should be specific for Strep antigen will also attack the tissue of the heart due to similarity of the heart’s antigen to the strep antigen Jone’s Criteria: 2 major or 1 major + 2 minor  Major Criteria Minor Criteria Carditis RHD or previous rheumatic fever  Polyarthritis Athralgia Chorea Fever  Subcutaneous nodules Elevated esr  Erythema marginatum Postive CrP Leukocytosis Prolonged PR interval on ECG

Acute Lesion Pancarditis (all layers) 

Pericarditis – fibrous type   Endocarditis – verrucae along lines of closure of valve leaflets   Myocarditis – Aschoff bodies in granulomatous stage (histologic hallmark of rheumatic ac tivity)

Pericarditis (Gross)

Fibrous type ( Bread and Butter Pericarditis)

Pericarditis (Microscopic)

Fibrin de osits

Epicardial layer 

Myocardial fibers

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 Rheumatic Heart Disease Endocarditis (Gross)

Mitral Valve (Translucent = Normal)

Verucae (Vesicle like structures)

Thickened Papillary Muscles

Endocarditis (Microscopic)

Fibrin deposits

 Neutrophilic infiltrations

Aschoff Bodies in Myocarditis • •

special type of interstitial inflammation a perivascular focus of swollen eosinophilic collagen surrounded by lymphocytes, monocytes and  plasma cells

Three Stages 1. Exudative stage 2. Granulomatous stage 3. Healed Stage

 HEC B5MD2011

 Pathology Cardiovascular Practicals Reviewer Page 8 of 20 Exudative Stage

Blood Vessel Lumen

Exudate with  Neutrophilic infiltrations

Cardiac Muscles

Granulomatous Stage

Granuloma formation (with epithelial histiocytes and macrophages)

Healed Stage Fibrosis around the BV

Blood Vessels

Myocardial layer 

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 Rheumatic Heart Disease Chronic Lesion • •

commisures fused; cusps thickened and fibrotic; chordae tendinae thickened, shortened and fused Most commonly involved valve- mitral, alone or in combination with others

Deformed orifice (Fish Mouth Deformity)

Fibrotic and smooth mitral valve

Fused Commisures

Short, thickened and fused together  Chordae tendinae

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 Infective Endocarditis • •

Invasion of the heart by microbiologic agent (friable vegetations laden with organisms) Predisposing factors: o Rheumatic heart disease (valves become fibrotic), congenital heart disease, calcific stenosis, artificial valves, immunodeficiency/ immunodepression, IV drug abuse

Types: ACUTE virulent organisms affects previously normal valve highly destructive  bulkier vegetations valve perforation common

SUBACUTE low virulence superimposed on damaged valves; less destructive smaller vegetations

Complications: Sepsis Cardiac – valve insufficiency, myocardial abscess Embolic Renal – embolic infarction, focal glomerulonephritis, abscesses • • • •

Aortic Valve

Bulky Vegetations

Vegetations

Perforation

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 Mitral Valve Prolapse (Floppy Valve) • • •

Degenerative change, in 6% of population, young women Accumulation of mucopolysaccharides in valve leaflet causing ballooning of the valve Myxomatous degeneration of spongiosa layer, degeneration & attenuation of fibrosa layer 

Three Layers of the Valve 1. Auricularis layer (from atrium) 2. Ventricularis layer (from ventricles) 3. Spongiosa layer Æ thickens

Complications Mitral Insufficiency Chordal rupture o Due to stretching Infective endocarditis • •

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Abundant amount of tissue (Bulging appearance)

Thin Ventricularis layer 

Thin Auricularis layer 

Thick Spongiosa layer  Myocardial layer 

Bulging Valve

Ruptured Chordae Tendinae Stretched Chordae Tendinae  HEC B5MD2011

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 Ischemic Heart Disease 

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Syndromes resulting from imbalance between supply and demand of the heart for oxygenation 1. Increased demand (increased heart rate) 2. Diminished oxygen transport (sever anemia, congenital h eart disease) 3. Diminished coronary blood flow Coronary atherosclerosis is the most common cause of diminished blood flow 1. 75% narrowing is significant 2. Stenosis within 2cm of left anterior descending and circumflex artery Ischemic syndromes 1. Angina pectoris 2. Myocardial infarct 3. Sudden cardiac death

Calcium deposits (make vessel more brittle)

Large deposits of  Atheromatous plaques

 Narrowed lumen

Blood clot (complete occlusion) ↑ BP Æ injures the surface of the blood

vessel Æ coagulation cascade Æ thrombus formation Æ blood clot

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 Myocardial Infarct  

Transmural – necrosis of full thickness of the LV wall, a ssociated with occlusive thrombi in 90% Subendocardial – necrosis limited to inner 1/3, diffuse coronary atherosclerosis, no thrombus

Infarct ( Left Main CA) Full Thickness of the Ventricle (Anterior wall, anterior 2/3 of septum and lateral ventricular wall)

Infarct ( Left Main CA and Right CA) (Anterior wall, anterior 2/3 of septum, lateral ventricular wall and posterior wall)

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 M   yocardial Infarct  ½ to 1 hr After Myocardial Infarct

Wavy myocardial fibers