Clinical pathology: comprehensive notes made easy on cardiovascular detailed and precise words

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Clinical Pathology: Cardiovascular System - Comprehensive Notes

Sources: Robbins & Kumar Basic Pathology; Robbins, Cotran & Kumar Pathologic Basis of Disease

1. ISCHEMIC HEART DISEASE (IHD)

Definition

IHD is a group of related syndromes caused by an imbalance between myocardial oxygen/nutrient supply (perfusion) and demand. Ischemia not only limits oxygen delivery (and thus ATP generation via oxidative phosphorylation) but also reduces nutrient supply and metabolic waste removal - making it less well tolerated than simple hypoxemia (e.g., anemia, cyanotic heart disease).

Epidemiology

Single largest cause of mortality worldwide, >15% of all global deaths; ~9 million deaths/year in high-resource countries
IHD mortality in the United States has fallen >50% since peaking in the mid-1960s
~800,000 Americans experience an MI each year; roughly half die

Etiology

>90% of cases: obstructive atherosclerotic lesions in epicardial coronary arteries (CAD)
Remaining causes: coronary emboli, vasculitis, vascular spasm (Prinzmetal), increased demand (tachycardia, hypertrophy), hypoxemia, systemic hypotension

Pathogenesis

Two key mechanisms:

Fixed (chronic) atherosclerotic occlusion - obstructions <70% of lumen are typically asymptomatic; critical stenosis at 70-75% causes symptoms with exertion; >90% may cause symptoms at rest
Acute plaque change with superimposed thrombosis/vasospasm - responsible for most acute coronary syndromes. Plaque disruption (rupture or erosion) exposes subendothelial collagen and thrombogenic material, triggering platelet aggregation and fibrin thrombus

Tachycardia is doubly harmful: increases oxygen demand (more contractions/unit time) AND decreases supply (less diastolic time, when coronary perfusion occurs).

Clinical Syndromes

Syndrome	Mechanism	Key Feature
Stable angina	Fixed stenosis; ischemia with exertion	Reversible; no necrosis
Vasospastic (Prinzmetal) angina	Coronary artery spasm	Occurs at rest; ST elevation
Unstable angina	Plaque disruption + partial thrombus	Increasing frequency/severity; rest pain
Myocardial infarction	Sustained ischemia causing necrosis	Irreversible cell death
Chronic IHD with CHF	Cumulative ischemic injury or post-MI	Progressive pump failure
Sudden cardiac death	Lethal ventricular fibrillation from ischemia	Usually within 1 hr of symptoms

Acute Coronary Syndrome (ACS) = unstable angina + MI + SCD

2. MYOCARDIAL INFARCTION (MI)

Pathogenesis

Most MIs (>90%) result from occlusive coronary thrombus superimposed on disrupted atherosclerotic plaque
STEMI: typically complete occlusion; transmural infarct
NSTEMI: partial or dynamic occlusion; subendocardial infarct (inner 1/3 of wall, most vulnerable due to highest wall stress and lowest perfusion pressure)

Sequence of Morphological Changes

Time	Gross	Microscopic
0-6 hrs	Normal (often undetectable)	Early coagulation necrosis; wavy fiber change
6-24 hrs	Dark mottling	Coagulation necrosis; pyknotic nuclei; marginated neutrophil infiltration begins
1-3 days	Pale/tan area; soft	Heavy neutrophil infiltration; myocyte nuclear loss
3-7 days	Yellow-tan, soft center; hyperemic border	Beginning macrophage infiltration; lysis of necrotic myocytes (PEAK RISK OF RUPTURE)
1-2 weeks	Depressed, gray-white border	Granulation tissue (macrophages + fibroblasts + new vessels)
2-8 weeks	Gray-white scar forming	Progressive collagen deposition
>2 months	White fibrous scar	Dense collagen scar; complete

Key point: Rupture risk is maximal at 3-7 days when necrotic myocardium is maximally lysed and converted to soft granulation tissue.

Histochemistry

Triphenyltetrazolium chloride (TTC): stains viable myocardium brick-red (NAD-dependent dehydrogenases intact); infarcted areas remain pale - useful within hours macroscopically

STEMI vs NSTEMI

Feature	STEMI	NSTEMI
Occlusion	Complete	Partial/dynamic
Infarct type	Transmural	Subendocardial
ECG	ST elevation + Q waves	ST depression/T-wave changes; no Q waves
Troponin	Elevated	Elevated
In-hospital mortality	~9%	~6%

Complications of MI

Nearly 75% of patients experience at least one complication:

Contractile dysfunction - proportional to volume of damage; cardiogenic shock occurs in ~10% of transmural MIs (typically when >40% LV damaged)
Papillary muscle dysfunction - ischemia without rupture; causes mitral regurgitation
Papillary muscle rupture - severe acute mitral regurgitation; rare but catastrophic
Free wall rupture - 1-3% of MIs; most common 3-7 days post-MI; causes hemopericardium and fatal cardiac tamponade; risk factors: age >60, female sex, hypertension, first MI, no prior LV hypertrophy
Ventricular septal rupture - creates VSD with left-to-right shunt
Right ventricular infarction - isolated in 1-3% of MIs; right heart failure; systemic hypotension
Arrhythmias - most common cause of pre-hospital death; ventricular fibrillation
Pericarditis (fibrinous) - epicardial friction rub; days 2-3 post-MI
Mural thrombus - on akinetic/dyskinetic endocardium; source of systemic emboli
Ventricular aneurysm - late complication; paradoxical systolic bulge; risk of thrombus, arrhythmia, CHF
Progressive late CHF - chronic ischemic heart disease

3. HYPERTENSIVE HEART DISEASE (HHD)

Systemic (Left-Sided) HHD

Diagnostic criteria (both required):

Left ventricular hypertrophy (concentric) in the absence of other cardiovascular pathology
Clinical history or pathologic evidence of hypertension in other organs

Pathogenesis: Chronic pressure overload → myocyte hypertrophy (adaptive) → eventually maladaptive → myocardial dysfunction, diastolic impairment, CHF, sudden death

Morphology:

Heart weight >500 g (normal 320-360 g for 60-70 kg individual)
LV wall thickness >2.0 cm (normal 1.2-1.4 cm)
Concentric hypertrophy (no dilation until late)
Microscopically: increased transverse myocyte diameter; nuclear enlargement and hyperchromasia ("boxcar nuclei"); interstitial and perivascular fibrosis

Clinical features:

Often asymptomatic; detected incidentally by ECG/echo
Can present as atrial fibrillation (from left atrial enlargement), CHF
Increased risk of heart failure, ventricular arrhythmias, sudden cardiac death, post-MI death, stroke
Effective BP control can prevent and even reverse hypertrophy

Pulmonary (Right-Sided) HHD - Cor Pulmonale

Right ventricular hypertrophy and dilation from pulmonary hypertension due to primary lung or pulmonary vascular disease
Causes: COPD (most common), interstitial fibrosis, pneumoconiosis, recurrent pulmonary thromboembolism, primary pulmonary hypertension, obstructive sleep apnea

4. VALVULAR HEART DISEASE

Types of Dysfunction

Stenosis: failure to open fully → obstructs forward flow → pressure overload proximal to valve → hypertrophy
Insufficiency/Regurgitation: failure to close fully → allows backflow → volume overload → dilation

Common Causes Summary

Valve Lesion	Primary Cause(s)
Aortic stenosis	Calcific degeneration of normal or bicuspid valve
Aortic insufficiency	Dilation of ascending aorta (hypertension, aging, Marfan, syphilitic aortitis)
Mitral stenosis	Rheumatic heart disease
Mitral insufficiency	Myxomatous degeneration (MVP), LV dilation (ischemic/non-ischemic HF), rheumatic

Calcific Aortic Stenosis

Most common valvular abnormality
Prevalence ~5% for age ≥65
Pathogenesis: recurrent chronic injury (hyperlipidemia, hypertension, inflammation) → deposition of hydroxyapatite (same calcium salt as in bone)
Bicuspid aortic valve (1-2% of births): two unequal cusps with midline raphe; develops stenosis 1-2 decades earlier than normal valves
Clinical triad: syncope, angina, CHF (each portends increasing mortality without intervention)

Mitral Valve Prolapse (Myxomatous Degeneration)

Ballooning of one or both mitral leaflets into the left atrium during systole
Affects 2-3% of adults; more common in women
Pathology: myxomatous change - interchordal ballooning, attenuation of the fibrosa layer, thickening of spongiosa with proteoglycan accumulation, stretching of chordae tendineae
Usually benign; complications: severe MR, infective endocarditis, arrhythmias, rarely sudden death

Rheumatic Heart Disease (RHD)

Consequence of rheumatic fever (group A beta-hemolytic Streptococcus pharyngitis) - immune-mediated
Acute rheumatic fever: pancarditis (endo-, myo-, pericarditis); Aschoff bodies (foci of fibrinoid necrosis surrounded by mononuclear cells including Anitschkow cells - caterpillar cells - hallmark lesion)
Chronic RHD: valvular fibrosis and calcification, predominantly mitral stenosis
Leaflet thickening, commissural fusion ("fish mouth" or "buttonhole" orifice), chordal shortening and fusion
Left atrial dilation → risk of atrial fibrillation and mural thrombus formation

5. INFECTIVE ENDOCARDITIS (IE)

Definition

Microbial infection (predominantly bacterial) of heart valves or mural endocardium → vegetations (thrombotic debris + organisms) + destruction of underlying tissue.

Classification

Feature	Acute IE	Subacute IE
Organisms	High virulence (S. aureus)	Low virulence (S. viridans)
Valve	Normal or abnormal	Usually abnormal/damaged
Course	Rapid destruction; weeks	Indolent; weeks to months
Treatment	Antibiotics + often surgery	Often antibiotics alone

Common Organisms by Setting

Normal valve / IV drug users: S. aureus (right-sided; tricuspid valve most often)
Damaged/abnormal valves (50-60%): Streptococcus viridans (normal oral flora)
Prosthetic valve <1-2 months post-op: S. aureus, S. epidermidis (skin flora)
Prosthetic valve >1 year post-op: Streptococci, S. aureus
HACEK group: Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella (oral commensals)
Culture-negative (~10% of cases): prior antibiotic use, fastidious organisms

Predisposing Conditions

Historically: rheumatic heart disease (now less common) Currently: mitral valve prolapse, calcific aortic stenosis, bicuspid aortic valve, prosthetic valves, congenital defects, IV drug use

Vegetations

Located on atrial surface of AV valves or ventricular surface of semilunar valves
Bulky, irregular, destructive; can extend onto chordae
Composed of fibrin, platelets, inflammatory cells, and organisms

Complications (mnemonic: FROME)

Fungemia/bacteremia spread - septic emboli
Rupture of leaflets - acute regurgitation
Osteomyelitis / abscess formation (ring abscess)
Metastatic infection - septic emboli → brain (abscess, infarct), kidney, spleen
Embolic strokes and infarcts

Clinical Signs (peripheral manifestations)

Osler nodes: painful tender nodules on finger/toe pads (immune complex deposition)
Janeway lesions: painless hemorrhagic macules on palms/soles (septic emboli)
Roth spots: retinal hemorrhages with pale center
Splinter hemorrhages: subungual linear hemorrhages
Petechiae: from emboli or vasculitis

6. CARDIOMYOPATHIES

Overview - Three Primary Types

Feature	Dilated (DCM)	Hypertrophic (HCM)	Restrictive (RCM)
Chamber size	Dilated (all 4)	Normal/small (LV)	Normal/small
Wall thickness	Normal or thin	Increased (asymmetric septal)	Normal/slightly increased
Systolic function	Decreased	Normal or hyperdynamic	Normal
Diastolic function	May be impaired	Impaired	Markedly impaired
Pathologic change	Dilation + fibrosis	Myocyte disarray + fibrosis	Interstitial fibrosis/infiltration

Dilated Cardiomyopathy (DCM)

Morphology: Progressive cardiac dilation and systolic dysfunction; all four chambers dilated; mural thrombi common; microscopically - myocyte hypertrophy, interstitial fibrosis, variable degeneration

Causes:

Genetic (familial ~50%): mutations in >20 genes - cytoskeletal (dystrophin), sarcolemmal, nuclear envelope (lamin A/C); titin (TTN) truncation mutations account for 10-20% of all DCM
Myocarditis (Coxsackie B virus) progressing to DCM
Alcohol (ethanol/acetaldehyde direct toxicity; thiamine deficiency → beriberi heart disease)
Peripartum (last trimester to 5 months postpartum; multifactorial)
Cardiotoxic chemotherapy (doxorubicin/anthracyclines)
Hemochromatosis, cobalt, cocaine

Clinical: Progressive CHF; embolic stroke from mural thrombus; arrhythmias; sudden death

Hypertrophic Cardiomyopathy (HCM)

Morphology: Massive cardiac hypertrophy, disproportionate septal thickening (asymmetric septal hypertrophy, ASH); the hypertrophied septum bulges into the LV outflow tract → dynamic obstruction; fibrous endocardial plaque on anterior mitral leaflet from contact with septum; microscopically - myocyte disarray (pathognomonic): haphazard arrangement of hypertrophied myocytes with interstitial fibrosis and bizarre-shaped nuclei

Pathogenesis: Autosomal dominant mutations in sarcomeric proteins - most commonly:

Beta-myosin heavy chain (MYH7)
Myosin binding protein C (MYBPC3)
Cardiac troponin T and I

Pathophysiology: Systolic function preserved or hyperdynamic; primary deficit is diastolic dysfunction (stiff, non-compliant ventricle) → impaired filling; dynamic LVOTO during systole (Venturi effect pulls anterior mitral leaflet toward septum - SAM = systolic anterior motion)

Clinical: Exertional dyspnea, syncope, angina; most common cause of sudden cardiac death in young athletes; harsh systolic ejection murmur (increases with Valsalva, decreases with squatting)

Restrictive Cardiomyopathy (RCM)

Morphology: Primary decrease in ventricular compliance → impaired diastolic filling; systolic function preserved; biatrial dilation from restricted filling; ventricles approximately normal size; interstitial fibrosis (patchy to diffuse)

Causes:

Idiopathic
Cardiac amyloidosis (most common secondary cause in the West) - AL or TTR
Sarcoidosis - non-caseating granulomas
Radiation-induced fibrosis
Hemochromatosis (iron deposition)
Endomyocardial fibrosis (Africa/tropical - parasitic; eosinophilia-related Loeffler endomyocarditis)
Fabry disease, Gaucher disease (metabolite accumulation)

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

Autosomal dominant; mutations in desmosomal proteins (plakophilin, desmoplakin, desmoglein)
Progressive replacement of RV myocardium with fibrofatty tissue
Right ventricular failure; ventricular arrhythmias; sudden cardiac death (especially in young athletes)
RV wall appears thinned and fatty on imaging; "epsilon wave" on ECG

7. CONGENITAL HEART DISEASE

Epidemiology

Affects ~1% of live births (~40,000 infants/year in USA)
12 entities account for 85% of cases

Frequency of Major Lesions

Malformation	%
Ventricular septal defect (VSD)	42%
Atrial septal defect (ASD)	10%
Pulmonary stenosis	8%
Patent ductus arteriosus (PDA)	7%
Tetralogy of Fallot	5%
Coarctation of aorta	5%
Atrioventricular septal defect	4%
Aortic stenosis	4%
Transposition of great arteries	4%

Pathogenesis

Faulty embryogenesis during gestational weeks 3-8
Unknown cause in ~90% of cases
Risk factors: maternal diabetes, hypertension, infections (rubella, CMV, coxsackie, parvovirus B19), drugs (phenytoin, retinoic acid), trisomy 21/18/13, Turner syndrome, family history

Shunts

Left-to-right (acyanotic initially): VSD, ASD, PDA, AV canal defect

Increased pulmonary blood flow → pulmonary hypertension → Eisenmenger syndrome (reversal to right-to-left shunt = late cyanosis)

Right-to-left (cyanotic from birth): Tetralogy of Fallot, Transposition of great arteries, Truncus arteriosus, Tricuspid atresia

Tetralogy of Fallot (most common cyanotic CHD)

Four components:

Pulmonary stenosis (infundibular/valvular)
VSD (large, perimembranous)
Overriding aorta (aorta straddles the VSD)
Right ventricular hypertrophy (consequence of outflow obstruction)

Cyanosis severity depends on degree of pulmonic stenosis
Squatting increases SVR → reduces right-to-left shunt → relieves cyanosis
Hypercyanotic ("Tet") spells: acute infundibular spasm → profound cyanosis

Coarctation of Aorta

Discrete narrowing of aorta, typically juxtaductal (near ligamentum arteriosum)
Male > Female; associated with bicuspid aortic valve (50-70%)
Infantile type (with PDA): cyanosis of lower body; heart failure in infancy
Adult type (post-ductal): upper extremity hypertension; weak/delayed femoral pulses; notching of ribs (from enlarged intercostal collaterals) on CXR; "3 sign" on CXR; often asymptomatic until adulthood

8. PERICARDIAL DISEASE

Acute Pericarditis

Fibrinous pericarditis: most common pattern post-MI (Dressler syndrome at 2-10 weeks), uremia, viral; "bread-and-butter" appearance grossly; friction rub on auscultation
Hemorrhagic pericarditis: TB, malignancy, trauma; cardiac tamponade risk
Purulent/suppurative: bacterial; requires drainage

Pericardial Effusion and Tamponade

Rapid accumulation of as little as 200 mL can cause tamponade (pericardium cannot acutely stretch)
Slowly accumulating effusions: up to 1-2 L may be tolerated
Beck's triad: hypotension + muffled heart sounds + elevated JVP
Pulsus paradoxus: >10 mmHg drop in systolic BP with inspiration

Constrictive Pericarditis

Fibrotic, calcified pericardium that restricts diastolic filling of all chambers
Causes: TB (worldwide most common), prior cardiac surgery, radiation, prior purulent pericarditis
Clinically mimics restrictive cardiomyopathy - distinguished by imaging (pericardial thickening/calcification) and hemodynamics

9. HEART FAILURE (CHF)

Pathophysiology

Left-sided failure: reduced LV output → reduced CO → renal hypoperfusion → RAAS activation → fluid retention; backward pressure → pulmonary congestion → pulmonary edema (dyspnea, orthopnea, paroxysmal nocturnal dyspnea)

Right-sided failure: backward pressure → systemic venous congestion → hepatomegaly (cardiac cirrhosis with chronic failure), ascites, dependent edema, jugular venous distension

Common causes of left heart failure: IHD, hypertension, cardiomyopathy, aortic/mitral valve disease Common causes of isolated right heart failure: cor pulmonale, pulmonic/tricuspid valve disease, LV failure extending to right side

Compensatory Mechanisms (Frank-Starling)

Ventricular dilation (volume overload): increases preload → increased stroke volume (up to a limit)
Hypertrophy: increases contractile mass
Neurohormonal activation: catecholamines, RAAS, ADH
These become maladaptive with sustained decompensation

Morphology of CHF

Left heart: dilated LV, thinned walls; "brown atrophy" of myocytes; microscopically - myocyte hypertrophy, vacuolization, interstitial fibrosis
Lungs: pulmonary edema; "heart failure cells" (hemosiderin-laden macrophages) in alveolar spaces
Liver: "nutmeg liver" (centrilobular congestion/necrosis); cardiac cirrhosis
Kidneys: prerenal azotemia
Spleen/portal: splenomegaly; peripheral edema

10. SUDDEN CARDIAC DEATH (SCD)

Unexpected death from cardiac causes within 1 hour of symptom onset (or during sleep)
80% of adult SCD due to IHD (usually VF from acute ischemia)
Young patients (<35 years): HCM most common structural cause; ARVC; channelopathies (long QT syndrome, Brugada syndrome); anomalous coronary artery origin; commotio cordis

Quick Review: Key Pathologic Pearls

Finding	Disease
Aschoff bodies + Anitschkow cells (caterpillar cells)	Rheumatic heart disease
Myocyte disarray + interstitial fibrosis	Hypertrophic cardiomyopathy
Fibrofatty replacement of RV	ARVC
"Boxcar nuclei" in myocytes	Hypertensive heart disease
Banana-shaped nucleus (Anitschkow cell)	Rheumatic carditis
Bulky destructive vegetations	Infective endocarditis
Small warty vegetations along line of closure	Rheumatic endocarditis
Small sterile vegetations + SLE	Libman-Sacks endocarditis
Bread-and-butter pericardium	Fibrinous pericarditis (post-MI, uremia)
Nutmeg liver	Right-sided CHF (hepatic congestion)
Heart failure cells (hemosiderin macrophages)	Pulmonary edema from left CHF
TTC pale staining	Acute MI (infarct not staining red)
"Buttonhole" mitral valve	Rheumatic mitral stenosis
Ballooning leaflets into LA during systole	Mitral valve prolapse

Sources: Robbins & Kumar Basic Pathology (9780323790185); Robbins, Cotran & Kumar Pathologic Basis of Disease (9780443264528)

Topic summary with common tested questions and buzzwords translated into simple words

Cardiovascular Pathology - Topic Summary, Buzzwords & Common Exam Questions

Plain-language guide for rapid review

HOW TO READ THIS GUIDE

Buzzword = the fancy medical term examiners use
Plain meaning = what it actually means in simple words
Red flag = the one fact that almost always appears in exam questions

SECTION 1: ISCHEMIC HEART DISEASE (IHD)

Core Concept in Plain Words

The heart muscle is starving for blood because the pipes feeding it (coronary arteries) are clogged with fatty plaques. When the shortage is mild, you get chest pain (angina). When the pipe fully blocks, the heart muscle dies = heart attack (MI).

Buzzword Decoder

Buzzword	Plain Meaning
Ischemia	Not enough blood reaching an organ
Atherosclerosis	Fat/cholesterol plaques building up inside artery walls
Plaque rupture	The plaque's cap cracks open, triggering a clot
Thrombus	Blood clot that forms on ruptured plaque
Angina pectoris	Chest pain from temporary heart starvation (no permanent damage)
Vasospastic / Prinzmetal angina	Chest pain from artery squeezing shut (spasm), not a clot
Acute Coronary Syndrome (ACS)	Umbrella term = unstable angina + heart attack + sudden death
Infarction	An area of tissue death from lack of blood
Transmural MI	Full-thickness heart wall death (all layers)
Subendocardial MI	Only inner layer of heart wall dies (partial thickness)
STEMI	Heart attack with full blockage = ST-elevation on ECG
NSTEMI	Heart attack with partial blockage = no ST elevation
Diastole	Heart relaxation phase - when coronary arteries fill with blood
Tachycardia	Fast heart rate - doubly dangerous: needs more oxygen AND gets less (less diastolic time)

Tested Facts / Common Questions

Q: What % of IHD cases are caused by atherosclerosis? A: >90%

Q: Fixed blockage must exceed what % to cause symptoms with exertion? At rest? A: Symptoms at exertion = 70-75%; Symptoms at rest = >90% occlusion

Q: Why is tachycardia especially bad for IHD patients? A: Two reasons - heart needs more oxygen (more beats), AND gets less blood (coronary filling happens during diastole, which shortens with fast rate)

Q: What is the "acute coronary syndrome" triad? A: Unstable angina + MI (STEMI/NSTEMI) + Sudden cardiac death

SECTION 2: MYOCARDIAL INFARCTION (MI)

Core Concept in Plain Words

The heart muscle actually dies. Cells die in a predictable sequence. Knowing the timeline = knowing when complications happen and what the tissue looks like.

Buzzword Decoder

Buzzword	Plain Meaning
Coagulation necrosis	Dead cells that keep their ghost outline for days (most organs do this)
Wavy fiber change	First visible sign at 6 hrs: heart fibers look wavy/buckled under microscope
Neutrophils	First immune cells to arrive; at the scene 1-3 days
Macrophages	Clean-up crew; arrive after neutrophils (day 3+)
Granulation tissue	Healing tissue (lots of tiny blood vessels + scar-forming cells)
Mural thrombus	Blood clot sitting on the inside wall of the dead heart zone
Ventricular aneurysm	Scarred, dead heart wall that bulges outward - a "bubble" in the wall
Fibrinous pericarditis	Inflammation of heart sac (rough, scratchy surface) - friction rub
Cardiogenic shock	Heart pumping so badly blood pressure crashes (<40% LV dead)
TTC stain	Lab stain: viable heart = brick red; dead heart = pale/white
Cardiac tamponade	Blood floods the heart sac → squeezes the heart → can't fill

The MI Timeline - Simplified

Time After MI	What You See	Exam Clue
0-6 hrs	Nothing visible (gross normal); wavy fibers under microscope	"Nothing seen but patient has chest pain + elevated troponin"
6-24 hrs	Pale/dark mottled area; neutrophils start arriving	Coagulation necrosis begins
1-3 days	Soft pale area; heavy neutrophil infiltration	Peak neutrophil zone
3-7 days	Soft, yellow, friable center; macrophages digesting dead tissue	PEAK RUPTURE RISK
1-2 weeks	Granulation tissue edges in from border	Red/vascular healing ring
2+ months	White fibrous scar; fully healed	Dense scar; permanent

Complications - When They Occur

Complication	When	Plain Meaning
Arrhythmia / VF	First hours	Electrical chaos = most common cause of death BEFORE hospital
Cardiogenic shock	Hours to days	Heart so damaged it can't pump; BP crashes
Fibrinous pericarditis	Days 2-3	Heart sac inflamed; hear "friction rub" with stethoscope
Rupture (free wall, septum, papillary)	Days 3-7	Worst timing = maximum tissue softness
Mural thrombus	Days to weeks	Clot on dead wall → can embolize to brain
Ventricular aneurysm	Weeks to months	Scar bulges outward; never fully contracts

Tested Facts / Common Questions

Q: What is the FIRST microscopic change after MI? A: Wavy fiber change (at ~6 hours)

Q: When is rupture risk highest? A: Days 3-7 - when macrophages have digested the dead tissue and it is softest

Q: What causes sudden death BEFORE the patient reaches the hospital? A: Ventricular fibrillation (from acute ischemia)

Q: What is TTC stain used for? A: Identifies infarcted areas - viable heart turns brick red; infarcted area stays pale

Q: What is cardiogenic shock threshold? A: Damage to >40% of left ventricular mass

Q: Beck's triad (cardiac tamponade)? A: Hypotension + muffled heart sounds + raised neck veins (JVP up)

SECTION 3: HYPERTENSIVE HEART DISEASE (HHD)

Core Concept in Plain Words

Chronically high blood pressure makes the heart pump against resistance - like blowing through a narrowed straw for years. The heart wall thickens (hypertrophy) to compensate. Eventually it stiffens, can't relax properly, and fails.

Buzzword Decoder

Buzzword	Plain Meaning
Concentric hypertrophy	Wall thickens inward; chamber stays small or normal; wall squeezes together
Eccentric hypertrophy	Wall thins and chamber dilates (volume overload pattern)
Pressure overload	Heart works against high resistance = hypertension, aortic stenosis
Volume overload	Heart has too much blood to pump = regurgitation, ASD, VSD
Diastolic dysfunction	Heart can't relax and fill properly (stiff)
"Boxcar nuclei"	Large, dark, rectangular-looking nuclei in hypertrophied heart cells - seen under microscope
Cor pulmonale	Right-sided hypertensive heart disease from lung disease
Atrial fibrillation	Irregular heart rhythm from left atrium being stretched

Tested Facts / Common Questions

Q: Minimum criteria for diagnosing HHD? A: (1) LV hypertrophy with no other cause + (2) evidence of hypertension somewhere in the body

Q: What is the characteristic microscopic finding in HHD? A: "Boxcar nuclei" - enlarged, hyperchromatic (dark) rectangular nuclei in myocytes + interstitial fibrosis

Q: Hypertension causes what type of hypertrophy? A: Concentric (wall thickens inward, chamber shrinks)

Q: What is cor pulmonale? A: Right ventricular hypertrophy/failure caused by lung disease (COPD, pulmonary fibrosis, PE, sleep apnea) - NOT caused by left heart disease

Q: Heart weight threshold for HHD? A: >500 g (normal ~320-360 g); LV wall >2.0 cm (normal 1.2-1.4 cm)

SECTION 4: VALVULAR HEART DISEASE

Core Concept in Plain Words

Heart valves control one-way blood flow. If a valve can't open fully (stenosis), blood backs up behind it and the chamber works too hard. If a valve can't close (regurgitation), blood leaks backward and the chamber fills with too much volume.

Buzzword Decoder

Buzzword	Plain Meaning
Stenosis	Valve stuck partially shut - forward flow blocked
Insufficiency / Regurgitation / Incompetence	Valve can't close properly - blood leaks backward
Bicuspid aortic valve	Born with only 2 leaflets instead of 3; wears out faster
Hydroxyapatite	The calcium salt that calcifies old valves (same as in bone)
Myxomatous degeneration	Valve leaflets become floppy and boggy - too much gel-like material
Aschoff body	Tiny knots of inflammation in rheumatic heart disease
Anitschkow cell (caterpillar cell)	Distinctive cell inside Aschoff bodies; looks like a caterpillar under microscope
"Fish mouth" / "Buttonhole" valve	Severely narrowed mitral valve opening in rheumatic disease
Commissural fusion	Leaflet edges get stuck together by scarring (rheumatic)
SAM (Systolic Anterior Motion)	In HCM, the mitral valve leaflet gets sucked into the outflow tract during systole

Aortic Stenosis - Key Points

Most common valvular abnormality overall
Calcification of: (1) normal valve in elderly (7th-9th decade) or (2) bicuspid valve earlier (5th-6th decade)
Symptoms = SAD triad: Syncope, Angina, Dyspnea/CHF
Average survival after symptoms: syncope = 3 yrs; angina = 5 yrs; CHF = 2 yrs

Mitral Valve Prolapse (MVP)

Most common valvular abnormality in developed countries (2-3% of adults)
Floppy leaflets balloon into left atrium during systole
Mid-systolic click + late systolic murmur on auscultation
Usually benign; complications rare: severe MR, infective endocarditis, sudden death

Rheumatic Heart Disease (RHD)

Caused by group A strep throat → immune cross-reaction damages the heart (molecular mimicry)
Acute phase: Aschoff bodies (hallmark) + Anitschkow cells
Chronic phase: mitral stenosis most common (then aortic, then tricuspid)
Mitral valve = "fish mouth" or "buttonhole" appearance
Complications: atrial fibrillation, mural thrombus, pulmonary hypertension, stroke

Tested Facts / Common Questions

Q: Most common cause of mitral stenosis? A: Rheumatic heart disease

Q: Most common cause of aortic stenosis? A: Calcific (degenerative) - age-related wear and tear on a normal or bicuspid valve

Q: Histologic hallmark of rheumatic heart disease? A: Aschoff body with Anitschkow cells (caterpillar cells)

Q: Bicuspid aortic valve is associated with what other lesion? A: Coarctation of the aorta (50-70% association)

Q: Stenosis causes what kind of overload? Regurgitation causes what kind? A: Stenosis = pressure overload → concentric hypertrophy; Regurgitation = volume overload → dilation (eccentric hypertrophy)

SECTION 5: INFECTIVE ENDOCARDITIS (IE)

Core Concept in Plain Words

Bacteria infect the heart valves and build "vegetations" - clumps of bacteria, fibrin, and debris. They can break off and travel anywhere in the body (brain, kidneys, fingers, eyes).

Buzzword Decoder

Buzzword	Plain Meaning
Vegetation	Infected clump on valve = bacteria + clot debris
Acute IE	Fast, aggressive infection on a normal valve (usually S. aureus)
Subacute IE	Slow, sneaky infection on damaged valve (usually Strep viridans)
Septic emboli	Chunks of infected vegetation breaking off → travel to organs
Osler nodes	Painful bumps on fingertips/toe pads - immune reaction (NOT bacteria directly)
Janeway lesions	Painless red spots on palms/soles - from actual tiny septic emboli
Roth spots	Red spots with pale center in the eye (retina)
Splinter hemorrhages	Tiny lines under fingernails - tiny emboli in nail beds
HACEK	Group of mouth bacteria that can cause IE
Ring abscess	Infection eating into the valve base/ring - surgical emergency

Memory Aid: Acute vs Subacute IE

Acute = Aggressive, Abnormal valve not needed, S. Aureus
Subacute = Slow and sneaky, Strep viridans, Scarred valve needed

Tested Facts / Common Questions

Q: Most common organism in IV drug users with IE? A: Staphylococcus aureus - affects RIGHT-SIDED valves, especially tricuspid

Q: Most common organism in IE on previously damaged valves? A: Streptococcus viridans (50-60% of native valve endocarditis)

Q: Painful nodules on fingertips in IE? A: Osler nodes (immune-mediated; "O" for Ouch)

Q: Painless hemorrhagic spots on palms/soles in IE? A: Janeway lesions (embolic; "J" for Just lying there painless)

Q: What type of vegetations are in IE vs Rheumatic fever? A: IE = large, bulky, destructive; Rheumatic fever = small, warty, along valve line of closure; NBTE = small, sterile; Libman-Sacks (lupus) = small, on BOTH sides of leaflet

Q: Culture-negative IE - what to think? A: Prior antibiotics given, OR fastidious organisms (HACEK group, Coxiella, Bartonella)

SECTION 6: CARDIOMYOPATHIES

Core Concept in Plain Words

The heart muscle itself is diseased - not from blocked arteries or valve problems. Three main patterns based on what the heart does wrong.

The 3 Types at a Glance

	Dilated (DCM)	Hypertrophic (HCM)	Restrictive (RCM)
What happens	Heart stretches and weakens; can't squeeze	Wall thickens massively; can't relax	Heart stiffens from infiltration; can't fill
Problem	Systolic (pump) failure	Diastolic (filling) failure	Diastolic (filling) failure
Chambers look like	Big floppy balloon	Thick-walled, small cavity	Normal size; stiff
Key microscopic finding	Myocyte hypertrophy + fibrosis	Myocyte DISARRAY + fibrosis	Interstitial fibrosis or infiltrate
Common cause	Alcohol, viral, genetic, chemo	Genetic (sarcomere mutations)	Amyloid, sarcoid, hemochromatosis
Main risk	CHF, stroke (mural thrombus), arrhythmia	Sudden death in young athletes	Progressive diastolic failure

Buzzword Decoder

Buzzword	Plain Meaning
Myocyte disarray	Heart cells pointing in all random directions instead of organized rows; pathognomonic for HCM
Asymmetric septal hypertrophy (ASH)	The wall between ventricles thickens more than the free wall
Dynamic LVOTO	Outflow from left ventricle gets blocked during systole - the thick septum gets in the way
Systolic anterior motion (SAM)	Mitral valve leaflet gets sucked toward thick septum during systole - worsens obstruction
Sarcomeric protein mutation	Genetic mutation in the heart's actual contraction machinery
Titin (TTN)	Largest human protein; spring-like scaffold in heart cell; most common gene mutated in DCM (10-20%)
Fibrofatty replacement	Normal muscle replaced by fat + fibrous tissue (ARVC pattern in RV)
Epsilon wave	Subtle ECG finding in ARVC - small blip after QRS
Amyloidosis	Abnormal protein deposits stiffening the heart - classic cause of RCM

Tested Facts / Common Questions

Q: Most common cause of sudden cardiac death in young athletes? A: Hypertrophic cardiomyopathy (HCM)

Q: Pathognomonic microscopic finding of HCM? A: Myocyte disarray (cells in chaotic arrangement instead of parallel rows)

Q: HCM murmur - what makes it louder? What makes it quieter? A: Louder with Valsalva maneuver or standing (less blood in LV → more obstruction); Quieter with squatting or lying down (more blood → less obstruction)

Q: Most common gene mutated in familial DCM? A: TTN (titin) - accounts for 10-20% of all DCM cases

Q: Which toxin causes DCM by direct myocardial injury? A: Alcohol (ethanol/acetaldehyde toxicity); also doxorubicin (chemotherapy)

Q: ARVC - what replaces the RV myocardium? A: Fibrofatty tissue (fat + fibrous scar replace normal muscle)

Q: Most common secondary cause of restrictive cardiomyopathy? A: Cardiac amyloidosis

SECTION 7: CONGENITAL HEART DISEASE

Core Concept in Plain Words

The heart is built wrong during fetal development. Some defects cause too much blood going to the lungs (left-to-right shunts = pink baby). Others cause blood bypassing the lungs completely (right-to-left shunts = blue baby from birth).

Buzzword Decoder

Buzzword	Plain Meaning
Left-to-right shunt	Blood leaks from high-pressure left side to lower-pressure right side → too much blood going to lungs
Right-to-left shunt	Blood bypasses the lungs → unoxygenated blood goes to body → CYANOSIS from birth
Eisenmenger syndrome	Long-standing L→R shunt causes pulmonary hypertension → RV pressure rises above LV → shunt reverses to R→L → late cyanosis
Overriding aorta	Aorta sits above the VSD instead of purely over the left ventricle
Infundibular stenosis	Narrowing of the muscular outflow just below the pulmonary valve (most common in TOF)
Juxtaductal coarctation	Narrowing right at the spot where the ductus arteriosus used to be
"Rib notching"	Enlarged intercostal arteries collateralizing around coarctation carve grooves into ribs, visible on CXR
"3 sign" on CXR	Appearance of coarctation on X-ray - aortic indentation makes a figure "3"
Tetralogy	Group of four defects (TOF = PS + VSD + overriding aorta + RVH)
Hypercyanotic ("Tet") spell	Sudden severe blue episode in TOF from infundibular spasm - child squats to relieve it

Left-to-Right vs Right-to-Left at a Glance

	L→R Shunt	R→L Shunt
Cyanosis at birth?	NO (acyanotic)	YES (cyanotic)
Examples	VSD, ASD, PDA	Tetralogy of Fallot, Transposition
Risk over time	Eisenmenger (reversal)	Polycythemia, clubbing, brain abscess
Most common	VSD (#1 overall CHD)	Tetralogy of Fallot (#1 cyanotic)

Tested Facts / Common Questions

Q: Most common congenital heart defect overall? A: Ventricular septal defect (VSD) - 42%

Q: Most common CYANOTIC congenital heart defect? A: Tetralogy of Fallot

Q: Four components of Tetralogy of Fallot? A: Pulmonic stenosis + VSD + Overriding aorta + RV hypertrophy (remember: PROVE: Pulmonic stenosis, Right ventricular hypertrophy, Overriding aorta, VSD)

Q: Why does squatting help a "Tet spell"? A: Squatting compresses femoral arteries → raises systemic resistance → reduces right-to-left shunt → more blood goes to lungs

Q: Coarctation is associated with which valve defect? A: Bicuspid aortic valve (50-70% of coarctation cases)

Q: What is Eisenmenger syndrome? A: Chronic L→R shunt → pulmonary hypertension → RV pressure exceeds LV → shunt reverses to R→L → late-onset cyanosis. At this stage, the defect is no longer surgically correctable.

SECTION 8: PERICARDIAL DISEASE

Buzzword Decoder

Buzzword	Plain Meaning
Fibrinous pericarditis	Rough, sandpaper-like heart sac; "bread and butter" look grossly; heard as friction rub
Cardiac tamponade	Fluid in heart sac squeezes the heart → can't fill → BP drops dangerously
Pulsus paradoxus	Blood pressure drops MORE than normal (>10 mmHg) when you breathe in - sign of tamponade
Beck's triad	Three findings of tamponade: low BP + muffled heart sounds + raised neck veins
Constrictive pericarditis	Chronic scarring/calcification of heart sac → squeezes heart permanently → can't fill
"Nutmeg liver"	Pattern of congestion in liver from right heart backup; alternating dark-red center + pale outside zones

Tested Facts / Common Questions

Q: What causes fibrinous pericarditis post-MI? A: Dressler syndrome (2-10 weeks post-MI) from immune reaction; also uremia, viral infection

Q: Minimum volume to cause tamponade if fluid accumulates rapidly? A: As little as 200 mL (pericardium can't stretch fast enough)

Q: What distinguishes constrictive pericarditis from restrictive cardiomyopathy? A: Constrictive pericarditis: pericardial thickening/calcification on imaging; responds to pericardiectomy. RCM: normal pericardium; myocardium abnormal on biopsy

Q: Most common cause of constrictive pericarditis worldwide? A: Tuberculosis (TB)

SECTION 9: HEART FAILURE

Buzzword Decoder

Buzzword	Plain Meaning
Systolic (HFrEF)	Heart can't squeeze enough → reduced ejection fraction
Diastolic (HFpEF)	Heart can't relax and fill → preserved ejection fraction but still fails
Orthopnea	Can't breathe lying flat - fluid in lungs redistributes with gravity
PND (Paroxysmal Nocturnal Dyspnea)	Wake up gasping at night from pulmonary edema
JVP / JVD	Jugular venous pressure/distension - neck veins bulging = blood backing up from right heart
Heart failure cells	Macrophages stuffed with hemosiderin (iron) found in lung fluid - sign of chronic pulmonary congestion
Cardiac cirrhosis	Long-standing right heart failure causes liver scarring from chronic congestion
RAAS activation	Kidneys sense low BP → retain salt and water → makes congestion worse
Brown atrophy	Heart cells shrink and turn brown from lipofuscin accumulation (wear-and-tear pigment)

Tested Facts / Common Questions

Q: What are "heart failure cells"? A: Hemosiderin-laden macrophages in the lung alveoli - macrophages that have engulfed red blood cells leaking from congested capillaries; stain blue with Prussian blue stain

Q: What is "nutmeg liver"? A: Chronic right heart failure causes blood to back up into liver → dark red centrilobular congestion zones surrounded by pale periportal areas → looks like cut nutmeg

Q: Left vs Right sided failure - what are the key symptoms? A: Left = pulmonary (breathlessness, orthopnea, PND, frothy sputum); Right = systemic (leg edema, JVD, hepatomegaly, ascites)

MASTER EXAM BUZZWORD TABLE

See/Hear This	Think This
Aschoff body + Anitschkow cell	Rheumatic heart disease
"Caterpillar cell" / "owl-eye nucleus" in heart	Anitschkow cell → Rheumatic fever
Myocyte disarray	HCM (hypertrophic cardiomyopathy) - pathognomonic
Boxcar nuclei	Hypertensive heart disease
Fibrofatty replacement of RV wall	ARVC
Small warty vegetations on valve closure line	Rheumatic endocarditis
Large bulky destructive vegetations	Infective endocarditis (S. aureus most aggressive)
Small sterile vegetations (marantic)	NBTE - Non-bacterial thrombotic endocarditis (cancer, SLE)
Vegetations on BOTH sides of leaflet	Libman-Sacks endocarditis (lupus/SLE)
Painful finger nodules + IE	Osler nodes
Painless palm/sole spots + IE	Janeway lesions
Bread and butter pericardium	Fibrinous pericarditis (post-MI uremia)
Nutmeg liver	Right heart failure (hepatic congestion)
Heart failure cells in lung	Left heart failure (chronic pulmonary edema)
Brown atrophy	Chronic heart failure / cachexia
TTC stain: pale area	Acute MI (infarcted zone)
Pale area on TTC at 24 hrs	Confirmed MI territory
Concentric hypertrophy	Pressure overload (hypertension, aortic stenosis)
Eccentric hypertrophy / dilation	Volume overload (regurgitation, VSD)
Fish mouth / buttonhole valve	Rheumatic mitral stenosis
Rib notching on CXR	Coarctation of the aorta
"3 sign" on CXR	Coarctation of the aorta
Young athlete + sudden death	HCM first; also ARVC, anomalous coronary, long QT
Squatting relieves cyanosis	Tetralogy of Fallot (Tet spell)
Right-sided IE in IV drug user	S. aureus affecting tricuspid valve
Late cyanosis after years of a "pink" heart defect	Eisenmenger syndrome
Epsilon wave on ECG	ARVC
SAM on echocardiogram	HCM (systolic anterior motion of mitral valve)

Sources: Robbins & Kumar Basic Pathology; Robbins, Cotran & Kumar Pathologic Basis of Disease

Be smart and real create mcqs , saqs and laqs with answers

I can see your curriculum schedule - Week 6 covers congenital heart diseases, heart failure, and Week 7 covers valvular heart diseases, infective endocarditis, rheumatic heart disease, and ischemic heart disease. I'll create exam-ready questions precisely aligned to your syllabus.

CARDIOVASCULAR PATHOLOGY — EXAM QUESTION BANK

MCQs + SAQs + LAQs with Full Answers

Aligned to Weeks 6 & 7 of your KMT/QP-07/COL curriculum

PART A: MULTIPLE CHOICE QUESTIONS (MCQs)

Each question has one best answer. Explanation follows each answer.

BLOCK 1 — CONGENITAL HEART DISEASES

MCQ 1. A 3-day-old male infant is noted to be cyanotic at birth. Echocardiography reveals four abnormalities: a large VSD, pulmonary stenosis, right ventricular hypertrophy, and an overriding aorta. Which statement BEST explains why this infant is cyanotic?

A) Too much blood is flowing to the lungs
B) The left ventricle cannot pump efficiently
C) Deoxygenated blood bypasses the lungs and enters the aorta
D) The aorta and pulmonary artery are transposed
E) The foramen ovale has failed to close

Answer: C

Explanation: This is Tetralogy of Fallot (TOF), the most common cyanotic congenital heart disease. The pulmonary stenosis obstructs RV outflow and creates a right-to-left shunt through the VSD - deoxygenated (blue) blood skips the lungs and goes directly into the overriding aorta and out to the body. The baby is blue from birth because blood is never fully oxygenated.

MCQ 2. A 6-month-old child with a known large ventricular septal defect develops increasing breathlessness and failure to thrive. What is the initial hemodynamic direction of the shunt through the VSD?

A) Right-to-left (deoxygenated blood to body)
B) Left-to-right (oxygenated blood to lungs)
C) Bidirectional with equal pressures
D) No shunting; just turbulence
E) Left-to-right in systole, right-to-left in diastole

Answer: B

Explanation: Initially, left ventricular pressure exceeds right ventricular pressure, so blood shunts LEFT to RIGHT through the VSD. This sends extra blood to the lungs (pulmonary overcirculation), causing pulmonary hypertension, breathlessness, and failure to thrive. Over years, if uncorrected, pulmonary pressure eventually exceeds systemic pressure → Eisenmenger syndrome (shunt reverses → R→L → late cyanosis).

MCQ 3. A 25-year-old woman develops progressive exertional dyspnea. On examination she has loud P2, upper extremity blood pressure of 160/90 mmHg, and weak femoral pulses. Chest X-ray shows notching of ribs 3-8 bilaterally. Which congenital lesion is most likely?

A) Atrial septal defect
B) Patent ductus arteriosus
C) Coarctation of the aorta
D) Pulmonary stenosis
E) Tetralogy of Fallot

Answer: C

Explanation: Rib notching (erosion of inferior rib margins by enlarged intercostal collateral arteries) + upper limb hypertension + weak/delayed femoral pulses = classic coarctation of the aorta (post-ductal/adult type). The collateral arteries develop because blood must find alternative routes past the narrowed aortic segment.

MCQ 4. Which congenital cardiac defect is MOST commonly associated with a bicuspid aortic valve?

A) Ventricular septal defect
B) Tetralogy of Fallot
C) Coarctation of the aorta
D) Atrial septal defect
E) Patent ductus arteriosus

Answer: C

Explanation: Bicuspid aortic valve is found in 50-70% of patients with coarctation of the aorta. This is a well-tested association. Bicuspid aortic valve (1-2% of births) also accelerates calcific aortic stenosis by 1-2 decades earlier than normal valves.

MCQ 5. An infant with Down syndrome (Trisomy 21) is most likely to have which congenital cardiac defect?

A) Tetralogy of Fallot
B) Transposition of great arteries
C) Atrioventricular septal defect (AV canal defect)
D) Tricuspid atresia
E) Coarctation of the aorta

Answer: C

Explanation: Trisomy 21 (Down syndrome) has the strongest association with AV canal (endocardial cushion) defects, particularly atrioventricular septal defect. About 40-50% of Down syndrome patients have congenital heart disease, and the AV canal defect is the most characteristic.

BLOCK 2 — HEART FAILURE

MCQ 6. A 65-year-old man with chronic congestive heart failure is found dead. At autopsy, the lungs contain numerous macrophages with brown granular cytoplasm in the alveolar spaces. Prussian blue staining of these cells would be POSITIVE. What are these cells?

A) Type II pneumocytes undergoing hyperplasia
B) Alveolar macrophages containing hemosiderin (heart failure cells)
C) Lipid-laden macrophages from pulmonary edema
D) Neutrophils from secondary bacterial pneumonia
E) Silica-laden macrophages from dust exposure

Answer: B

Explanation: Heart failure cells = alveolar macrophages stuffed with hemosiderin (broken-down iron from red blood cells that leaked out of congested capillaries). They are found in chronic LEFT heart failure because elevated pulmonary venous pressure causes RBCs to leak into alveoli. Prussian blue stain confirms iron content. These are a hallmark of chronic pulmonary congestion.

MCQ 7. A 70-year-old woman with long-standing right-sided heart failure has a liver biopsy showing alternating areas of dark red centrilobular necrosis and pale periportal areas. What is this pattern called?

A) Bridging fibrosis
B) Geographic necrosis
C) Nutmeg liver
D) Balloon cell change
E) Steatohepatitis

Answer: C

Explanation: "Nutmeg liver" - chronic right heart failure causes blood to back up through the inferior vena cava into the hepatic veins. This congests the centrilobular (zone 3) hepatocytes first (they are furthest from the portal blood supply). The alternating dark congested centers + pale uncongested periportal areas look like a cut nutmeg. Long-standing congestion leads to cardiac cirrhosis.

MCQ 8. A patient with acute left ventricular failure wakes at 3 AM gasping for air, sits bolt upright, and improves after 20 minutes. What term describes this symptom?

A) Orthopnea
B) Platypnea
C) Trepopnea
D) Paroxysmal nocturnal dyspnea
E) Cheyne-Stokes respiration

Answer: D

Explanation: Paroxysmal Nocturnal Dyspnea (PND) - when lying flat for hours, fluid redistributes from dependent areas into the pulmonary circulation. The overloaded left ventricle cannot handle this extra blood. The patient wakes acutely breathless. Orthopnea = breathlessness immediately on lying flat, relieved by propping up with pillows.

MCQ 9. Which ONE mechanism BEST explains why the kidneys worsen heart failure by retaining salt and water?

A) Reduced aldosterone secretion
B) Low cardiac output → reduced renal perfusion → RAAS activation → Na+ and water retention
C) Elevated BNP suppresses tubular reabsorption
D) Increased atrial stretch → decreased ADH release
E) Diuretic-induced hyponatremia

Answer: B

Explanation: Low cardiac output → kidneys sense decreased perfusion pressure → activate the Renin-Angiotensin-Aldosterone System (RAAS) → aldosterone causes sodium + water retention → worsens fluid overload → worsens congestion. This is a vicious cycle. BNP (B-type natriuretic peptide) actually opposes this (released from stretched ventricles to promote natriuresis), but the RAAS effect dominates in severe failure.

BLOCK 3 — VALVULAR HEART DISEASES

MCQ 10. A 72-year-old man presents with exertional syncope, angina, and progressive dyspnea over 2 years. On auscultation there is a harsh crescendo-decrescendo systolic murmur at the right upper sternal border radiating to the neck. Echocardiography shows a heavily calcified aortic valve. What is the most likely diagnosis?

A) Mitral valve prolapse
B) Aortic regurgitation
C) Hypertrophic cardiomyopathy
D) Calcific aortic stenosis
E) Pulmonary stenosis

Answer: D

Explanation: The clinical triad of syncope + angina + dyspnea/CHF = aortic stenosis. The harsh systolic ejection murmur at the right upper sternal border (aortic area) radiating to the neck is classic for aortic stenosis. Age 72 + heavily calcified = calcific/degenerative aortic stenosis. The order of symptom appearance matters: angina appears first (5-year survival), then syncope (3 years), then CHF/dyspnea (2 years) - without intervention.

MCQ 11. A 35-year-old woman has a "fish mouth" appearance of her mitral valve on echocardiography. She has a history of recurrent sore throats in childhood and now has an irregular pulse. Which pathological process BEST explains her mitral stenosis?

A) Calcific degeneration from aging
B) Myxomatous degeneration of valve leaflets
C) Rheumatic fever - immune-mediated leaflet scarring and commissural fusion
D) Infective endocarditis with vegetation obstructing the valve
E) Carcinoid syndrome with right-sided fibrosis

Answer: C

Explanation: "Fish mouth" / "buttonhole" mitral valve = rheumatic mitral stenosis. Rheumatic fever (from Group A Strep throat) causes immune-mediated damage to valve leaflets + commissural fusion + chordal shortening. Mitral stenosis is the most common sequel of RHD. Left atrial enlargement from the obstruction leads to atrial fibrillation (the irregular pulse). Most common valvular disease from RHD.

MCQ 12. On routine auscultation of a 28-year-old woman, a mid-systolic click followed by a late systolic murmur is heard. Echocardiography shows posterior leaflet ballooning into the left atrium during systole. What is the most likely diagnosis?

A) Rheumatic mitral stenosis
B) Mitral valve prolapse (myxomatous degeneration)
C) Infective endocarditis
D) Calcific mitral annular ring
E) Papillary muscle rupture post-MI

Answer: B

Explanation: Mid-systolic CLICK + late systolic murmur = Mitral Valve Prolapse (MVP). The click is from the sudden tensing of the prolapsing leaflet. Affects 2-3% of adults; more common in women. Most are benign. The leaflets show myxomatous degeneration - increased spongiosa layer with proteoglycan accumulation, attenuated fibrosa layer, making them floppy and billowing.

MCQ 13. A pathologist examining a surgically removed mitral valve finds small, warty, 1-2 mm vegetations arranged along the LINE OF CLOSURE of the leaflet. The underlying leaflet architecture is preserved. What is the MOST LIKELY diagnosis?

A) Infective endocarditis
B) Non-bacterial thrombotic endocarditis (NBTE)
C) Rheumatic endocarditis
D) Libman-Sacks endocarditis
E) Carcinoid syndrome

Answer: C

Explanation: Small warty vegetations along the LINE OF CLOSURE (the zone where leaflets meet when closed) with preserved underlying architecture = Rheumatic endocarditis (active rheumatic fever). Contrast: IE = large, bulky, destructive, anywhere on leaflet; NBTE = small, sterile, along line of closure but in debilitated/cancer patients; Libman-Sacks (lupus) = vegetations on BOTH surfaces of leaflet.

MCQ 14. Libman-Sacks endocarditis is MOST strongly associated with which systemic condition?

A) Rheumatoid arthritis
B) Systemic lupus erythematosus (SLE)
C) Infective endocarditis from IV drug use
D) Marfan syndrome
E) Carcinoid tumor

Answer: B

Explanation: Libman-Sacks endocarditis = sterile vegetations on BOTH sides of the valve leaflet (unique characteristic) - pathognomonic of SLE. The antiphospholipid antibody syndrome (often in SLE) predisposes to sterile thrombotic vegetations. Key distinguisher from all other endocarditides: involvement of BOTH surfaces of the leaflet.

BLOCK 4 — INFECTIVE ENDOCARDITIS

MCQ 15. A 22-year-old intravenous heroin user presents with high fever, rigors, and a new holosystolic murmur. Blood cultures grow Staphylococcus aureus. Echocardiography shows large vegetations on the tricuspid valve. Which statement is CORRECT?

A) This is subacute endocarditis with a low virulence organism
B) Right-sided IE in IV drug users typically affects the mitral valve
C) S. aureus is the most common organism in IV drug user endocarditis and typically affects the tricuspid valve
D) Culture-negative IE is common in IV drug users
E) Osler nodes are always present

Answer: C

Explanation: IV drug use → skin flora introduced directly into the venous system → first valve encountered = tricuspid. S. aureus (skin/needle contamination) is the leading organism. This is ACUTE IE (S. aureus = highly virulent, rapidly destructive). Septic emboli from the right side go to the LUNGS (not brain/kidney as in left-sided IE).

MCQ 16. A patient with a known damaged mitral valve develops fever, new murmur, and microscopic hematuria. Three blood cultures are all NEGATIVE. Which organism is LEAST likely to be responsible?

A) Streptococcus viridans
B) HACEK group organisms
C) Coxiella burnetii (Q fever)
D) Staphylococcus aureus
E) Bartonella species

Answer: D

Explanation: S. aureus is highly virulent, grows readily in standard blood cultures, and is very rarely culture-negative. Culture-negative IE is typically caused by: prior antibiotic use, HACEK group (fastidious slow-growers), Coxiella burnetii (Q fever), Bartonella, and Tropheryma whipplei. S. viridans can also occasionally be difficult to grow.

MCQ 17. A patient with infective endocarditis develops painful, tender nodules on the pads of the fingers. These are caused by:

A) Septic emboli depositing bacteria in fingertip arteries
B) Immune complex deposition causing small vessel vasculitis
C) Calcium deposits from valve calcification
D) Microthrombi from antiphospholipid syndrome
E) Direct skin invasion by bacteria

Answer: B

Explanation: Osler nodes (painful tender nodules on finger/toe pads) = immune complex-mediated vasculitis. They are NOT direct emboli. Contrast with Janeway lesions (painless hemorrhagic macules on palms/soles) which ARE from septic emboli. Memory trick: Osler nodes = "Ouch" (painful) = immune; Janeway = "Just there" (painless) = embolic.

BLOCK 5 — ISCHEMIC HEART DISEASE

MCQ 18. A 55-year-old man with crushing central chest pain for 3 hours is taken to the mortuary after collapsing at home. At autopsy, the heart appears grossly NORMAL. Histology shows wavy fiber change and early coagulation necrosis without inflammatory infiltrate. What do these findings confirm?

A) The patient had no cardiac pathology
B) Acute MI less than 6 hours old
C) Chronic IHD with old scar
D) Hypertrophic cardiomyopathy
E) Myocarditis

Answer: B

Explanation: Gross appearance is NORMAL in the first 6 hours of MI (the classic exam trap). Histologically, wavy fiber change (heart cells buckle from being pulled by adjacent contracting muscle) and early coagulation necrosis are the FIRST microscopic changes. Neutrophils have not yet arrived (they start at 6-12 hours). TTC staining would show a pale (unstained) infarct zone.

MCQ 19. During autopsy of an MI patient who died 5 days after the acute event, the pathologist notes the infarcted zone is yellow-tan, soft, and mushy. Which complication is MAXIMALLY at risk at this time?

A) Arrhythmia
B) Cardiogenic shock
C) Myocardial rupture
D) Ventricular aneurysm
E) Pericarditis

Answer: C

Explanation: Days 3-7 = PEAK RUPTURE RISK. At this time, macrophages have maximally digested (lyzed) the necrotic myocardium, converting it into soft, friable granulation tissue. The wall is at its weakest. Free wall rupture → hemopericardium + tamponade. Septal rupture → VSD. Papillary muscle rupture → acute severe mitral regurgitation. The yellow-tan soft appearance describes this exact stage.

MCQ 20. A patient in the coronary care unit develops sudden hypotension, muffled heart sounds, and markedly distended neck veins on day 5 post-STEMI. ECG shows electrical alternans. What is the MOST likely diagnosis?

A) Acute mitral regurgitation from papillary muscle rupture
B) Right ventricular infarction
C) Cardiac tamponade from free wall rupture
D) Ventricular tachycardia
E) New VSD from septal rupture

Answer: C

Explanation: Beck's triad (hypotension + muffled heart sounds + raised JVP) + day 5 post-MI + electrical alternans on ECG = cardiac tamponade from free wall rupture. The free wall rupture releases blood into the pericardial sac, which compresses the heart. Electrical alternans (QRS alternates in axis) is a specific ECG sign of pericardial effusion/tamponade. This is rapidly fatal.

MCQ 21. Which type of angina occurs WITHOUT exertion, is associated with ST ELEVATION during episodes, and is caused by coronary artery spasm rather than fixed stenosis?

A) Stable angina
B) Unstable angina
C) Prinzmetal (vasospastic) angina
D) Microvascular angina
E) Decubitus angina

Answer: C

Explanation: Prinzmetal/vasospastic angina = episodes at REST, often at night or early morning; caused by coronary artery SPASM (not fixed plaque); shows transient ST ELEVATION during pain (not depression as in demand ischemia). Often responds to calcium channel blockers. Triggered by cocaine, smoking, cold. The vessel is not fixed-blocked - it intermittently clamps shut.

MCQ 22. Troponin I and Troponin T are the preferred biomarkers for diagnosing acute MI because:

A) They rise within 30 minutes of symptom onset
B) They are specific to cardiac myocytes and remain elevated for 7-10 days (troponin I) to 14 days (troponin T)
C) They are elevated in all types of angina
D) They are the first cardiac enzymes to normalize after MI
E) They replace the need for ECG in diagnosis

Answer: B

Explanation: Cardiac troponins (cTnI and cTnT) are cardiac-specific structural proteins released from damaged/dead myocytes. They rise at 3-6 hours after MI, peak at 24-48 hours, and REMAIN ELEVATED for 7-14 days - making them useful for detecting recent (even missed) MI. Their cardiac-specificity distinguishes MI from skeletal muscle injury. They do NOT rise in angina alone (no cell death).

PART B: SHORT ANSWER QUESTIONS (SAQs)

Each worth 5-10 marks. Write in structured, precise paragraphs.

SAQ 1 — Congenital Heart Disease

"Describe the pathology and hemodynamic consequences of Tetralogy of Fallot." (5 marks)

Model Answer:

Definition and Components (2 marks): Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect, characterized by four anatomical abnormalities that occur together due to anterior malalignment of the infundibular septum:

Pulmonary stenosis (infundibular or valvular - the most critical component)
Large perimembranous ventricular septal defect (VSD)
Overriding aorta (aorta sits above the VSD, straddling both ventricles)
Right ventricular hypertrophy (compensatory response to outflow obstruction)

Hemodynamic Consequence (2 marks): Pulmonary stenosis creates resistance to right ventricular outflow. Because pulmonary resistance exceeds systemic resistance, blood shunts RIGHT-TO-LEFT through the VSD. Deoxygenated blood enters the overriding aorta and is distributed to the body without being oxygenated - producing cyanosis from birth. The degree of cyanosis is directly proportional to the severity of pulmonary stenosis.

Hypercyanotic Spells (1 mark): "Tet spells" occur when infundibular muscle spasm acutely worsens obstruction. The child becomes profoundly cyanotic, restless, and may lose consciousness. Squatting is a compensatory mechanism - it increases systemic vascular resistance by compressing femoral arteries, reduces the right-to-left shunt, and forces more blood through the pulmonary circulation, temporarily improving oxygenation.

SAQ 2 — Heart Failure

"List the morphological changes found in chronic congestive heart failure, specifying changes in the heart, lungs, and liver." (6 marks)

Model Answer:

Heart (2 marks):

Dilation of all four chambers (especially left heart in left-sided failure)
Ventricular hypertrophy (concentric in early hypertension; eccentric/dilated in end-stage)
Mural thrombi on endocardial surface of hypokinetic walls
Microscopically: myocyte hypertrophy with large "boxcar" nuclei, vacuolar degeneration, interstitial fibrosis, and brown atrophy (accumulation of lipofuscin wear-and-tear pigment)

Lungs (2 marks):

Pulmonary edema - fluid in alveoli and interstitium (from raised pulmonary venous pressure in left heart failure)
"Heart failure cells" - hemosiderin-laden alveolar macrophages (pathognomonic); formed when RBCs leak from congested capillaries into alveoli and are phagocytosed; stain blue with Prussian blue stain
Interstitial fibrosis in chronic cases

Liver (2 marks):

"Nutmeg liver" (grossly): alternating dark red centrilobular congestion/necrosis surrounded by pale periportal zones, resembling a cross-section of nutmeg
Centrilobular hepatocyte necrosis (zone 3 most vulnerable - furthest from portal blood)
Long-standing congestion → fibrosis → "cardiac cirrhosis"
Splenomegaly and ascites from portal hypertension

SAQ 3 — Rheumatic Heart Disease

"Describe the pathogenesis and pathological features of rheumatic heart disease." (6 marks)

Model Answer:

Pathogenesis (2 marks): Rheumatic fever follows pharyngeal infection with Group A beta-hemolytic Streptococcus (Streptococcus pyogenes). The M-proteins of the organism share structural similarity with cardiac antigens (particularly myosin, tropomyosin, and valve proteins). This molecular mimicry triggers cross-reactive antibodies and T-lymphocytes that attack cardiac tissues. It is NOT direct bacterial infection of the heart.

Acute Rheumatic Carditis (2 marks): Pancarditis affects all three layers:

Pericarditis: fibrinous "bread and butter" pericarditis
Myocarditis: Aschoff bodies (pathognomonic) - foci of fibrinoid necrosis surrounded by macrophages (Anitschkow cells / caterpillar cells), lymphocytes, and plasma cells. Anitschkow cells have a central ribbon-like nucleus resembling a caterpillar
Endocarditis: small, warty 1-2 mm vegetations along the LINE OF CLOSURE of valve leaflets (McCallum's patch on posterior left atrial wall)

Chronic RHD (2 marks): Repeated attacks lead to progressive valvular scarring:

Leaflet fibrosis and thickening
Commissural fusion (leaflet edges scar together)
Chordal shortening and fusion
Calcification in chronic cases
Mitral valve most affected (100% in severe disease) followed by aortic (65%), tricuspid, and rarely pulmonary. The characteristic deformed mitral valve has a "fish mouth" or "buttonhole" appearance on gross inspection. Chronic mitral stenosis → left atrial dilation → atrial fibrillation → mural thrombus → stroke risk.

SAQ 4 — Infective Endocarditis

"Compare and contrast acute and subacute infective endocarditis under the headings: causative organism, valve affected, pathological features, and complications." (8 marks)

Model Answer:

Feature	Acute IE	Subacute IE
Organism	S. aureus (most common); highly virulent	S. viridans (50-60% of native valve IE); low virulence
Valve affected	Normal or previously damaged valves	Almost always previously damaged or abnormal valve
Vegetation character	Large (>2 cm), bulky, irregular, friable, destructive; may extend onto chordae tendineae	Smaller, less destructive; do not typically extend to chordae
Underlying tissue	Marked leaflet destruction, abscess formation (ring abscess), perforation	Less destruction; scarring and fibrosis
Course	Rapid (days to weeks); life-threatening	Indolent (weeks to months); more amenable to antibiotics alone
Complications	Perforation, abscess, septic emboli to brain/kidney/spleen, paravalvular abscess, fistula	Embolic phenomena (less common); immune complex glomerulonephritis; CHF from valve destruction

Peripheral Signs of IE (applicable to both, more common in subacute):

Osler nodes: painful fingertip nodules (immune complex vasculitis - "immune")
Janeway lesions: painless hemorrhagic palmar/plantar macules (septic emboli - "embolic")
Roth spots: retinal hemorrhages with white center
Splinter hemorrhages: linear subungual hemorrhages
Microscopic hematuria: immune complex glomerulonephritis

SAQ 5 — Ischemic Heart Disease

"Describe the sequence of morphological changes in the myocardium following acute MI over a 2-month period." (6 marks)

Model Answer:

0-6 Hours (1 mark):

Gross: No visible change (normal appearing heart)
Microscopy: Wavy fiber change (the earliest sign - myofibers buckle due to being pulled by adjacent contracting muscle); early coagulation necrosis begins; intracellular enzyme and troponin leak begins

6-24 Hours (1 mark):

Gross: Subtle pale/dark mottling
Microscopy: Coagulation necrosis established; pyknotic (dark, condensed) nuclei; cytoplasmic eosinophilia increases; neutrophil margination begins at 12 hours

1-3 Days (1 mark):

Gross: Well-defined pale/tan-yellow area
Microscopy: Dense neutrophil infiltration (peak neutrophil response); loss of nuclear detail

3-7 Days - CRITICAL PERIOD (1 mark):

Gross: Soft, yellow-tan, mushy infarct center with hyperemic (red) border
Microscopy: Macrophage infiltration begins; macrophages phagocytose necrotic debris (granuloma-like digestion); maximum tissue softening - PEAK RUPTURE RISK
Complications: Free wall rupture → tamponade; papillary muscle rupture → mitral regurgitation; septal rupture → VSD

1-2 Weeks (1 mark):

Gross: Depressed center with red/gray vascular border
Microscopy: Granulation tissue (macrophages + fibroblasts + neovascularization) grows in from border; collagen deposition begins

2+ Months (1 mark):

Gross: White, fibrous, depressed scar
Microscopy: Dense fibrous scar replaces necrotic myocardium; no residual inflammation
Consequence: Permanent loss of contractile function in scarred region; aneurysm formation if large area affected

PART C: LONG ANSWER QUESTIONS (LAQs)

Each worth 15-20 marks. Structured headings required.

LAQ 1 — Ischemic Heart Disease

"Write a comprehensive account of ischemic heart disease (IHD) under the following headings: definition, epidemiology, pathogenesis, clinical syndromes, pathological changes in MI, complications of MI, and morphological changes of healing." (20 marks)

Model Answer:

1. Definition (1 mark) IHD is a group of clinically related syndromes resulting from an imbalance between myocardial oxygen supply (perfusion) and demand. In >90% of cases, this is caused by obstructive coronary atherosclerosis - hence IHD is largely synonymous with coronary artery disease (CAD). Unlike simple hypoxemia, ischemia is particularly damaging because it simultaneously reduces oxygen delivery, depletes nutrients, AND prevents removal of toxic metabolic wastes.

2. Epidemiology (1 mark) IHD is the single largest cause of death worldwide - responsible for >15% of all global mortality (~9 million deaths/year in developed countries). In the USA, ~800,000 MIs occur annually. Mortality has fallen >50% since the 1960s due to modifiable risk factor control (smoking, hypertension, dyslipidemia) and therapeutic advances (statins, aspirin, PCI, CABG, thrombolysis).

3. Pathogenesis (4 marks)

Chronic Fixed Occlusion: Atherosclerotic plaques develop over decades in epicardial coronary arteries. The lumen must be reduced by 70-75% before exertional symptoms appear; >90% stenosis may cause resting ischemia.

Acute Plaque Change (Dynamic): The precipitating event in most acute MIs is sudden disruption of a previously stable (often non-obstructive) plaque. Disruption exposes the lipid core and subendothelial collagen, triggering:

Platelet adhesion and aggregation
Activation of the coagulation cascade
Formation of an occlusive fibrin-rich thrombus
Vasospasm from platelet-released thromboxane A2 and serotonin

Other Mechanisms: Coronary emboli; arteritis (Kawasaki disease); vasospasm (Prinzmetal); increased demand from tachycardia (simultaneously increases O2 need and reduces diastolic coronary filling time); hypotension; anemia.

4. Clinical Syndromes (3 marks)

Syndrome	Mechanism	Features
Stable angina	Fixed stenosis; demand-supply mismatch with exertion	Predictable; relieved by rest/nitrates; no necrosis
Unstable angina	Plaque disruption + partial/dynamic thrombus	Increasing frequency; occurs at rest; troponin negative
Prinzmetal angina	Coronary vasospasm	Rest pain; ST elevation; calcium channel blocker responsive
STEMI	Complete coronary occlusion	Transmural infarct; ST elevation; troponin positive
NSTEMI	Partial/dynamic occlusion	Subendocardial infarct; no Q waves; troponin positive
Sudden cardiac death	VF from acute ischemia	Death within 1 hour; most die before reaching hospital
Chronic IHD + CHF	Cumulative ischemic/infarction damage	Progressive pump failure; multiple infarct scars

5. Pathological Changes in MI (4 marks)

Gross Changes:

0-6 hrs: No gross change (TTC stain shows pale non-staining zone)
6-24 hrs: Dark mottling; pale/tan softening
1-3 days: Yellow-tan pale infarct, soft
3-7 days: Maximally soft, yellow, friable - PEAK RUPTURE RISK
1-2 weeks: Gray-white granulation tissue margin
2 months: Dense white fibrous scar

Microscopic Changes:

First 6 hrs: Wavy fiber change (earliest); beginning coagulation necrosis; no inflammation
12-24 hrs: Neutrophil infiltration begins; pyknotic nuclei; eosinophilic cytoplasm
Day 3-5: Heavy neutrophilic infiltrate; nuclear loss; macrophages appear
Week 1-2: Macrophages digesting debris; granulation tissue (fibroblasts + new capillaries) growing in from viable edges
Week 2+: Progressive collagen deposition; fibrous scar formation
2 months: Dense collagenous scar; complete healing

6. Complications of MI (5 marks)

Early (days 1-7):

Arrhythmias (most common; VF = most common cause of pre-hospital death)
Cardiogenic shock (>40% LV damage; 10% of transmural MI; high mortality)
Papillary muscle dysfunction / rupture → acute mitral regurgitation
Free wall rupture (day 3-7) → hemopericardium → cardiac tamponade (Beck's triad: hypotension + muffled sounds + elevated JVP)
Ventricular septal rupture → acute VSD → left-to-right shunt
Right ventricular infarction (RCA occlusion) → right heart failure
Fibrinous pericarditis (day 2-3) → friction rub on auscultation

Late (weeks to months):

Mural thrombus on akinetic endocardium → systemic emboli (stroke)
Left ventricular aneurysm → wall bulges during systole; arrhythmias; CHF; thrombus
Dressler syndrome (2-10 weeks): autoimmune fibrinous pericarditis
Chronic ischemic heart disease → progressive CHF

7. Healing and Repair (2 marks) After MI, necrotic myocardium cannot regenerate (adult cardiomyocytes are post-mitotic and have negligible regenerative capacity). Healing occurs exclusively by scar formation:

Phase 1 (days 3-7): Macrophage-mediated phagocytosis of dead tissue
Phase 2 (days 7-21): Granulation tissue - angiogenesis + fibroblast proliferation + collagen type III deposition
Phase 3 (weeks to months): Maturation - collagen type I replaces type III → dense, tough, contracted white scar
The scar is non-contractile and non-excitable → permanently impairs ventricular function proportional to size

LAQ 2 — Valvular Heart Disease

"Discuss the etiology, pathology, hemodynamic effects, and clinical features of the following valvular heart diseases: (a) calcific aortic stenosis, (b) mitral stenosis due to rheumatic heart disease, and (c) infective endocarditis." (15 marks)

Model Answer:

A. Calcific Aortic Stenosis (5 marks)

Etiology: Most common valvular abnormality overall. Results from age-related wear-and-tear calcification of:

Anatomically normal valves (presents in 7th-9th decade; "degenerative aortic stenosis")
Congenitally bicuspid aortic valve (1-2% of population; presents 1-2 decades earlier; 5th-6th decade) Pathogenesis resembles atherosclerosis: repetitive mechanical injury + hyperlipidemia + hypertension + inflammation → deposition of hydroxyapatite calcium salt in leaflet tissue.

Pathology:

Gross: Heavy calcium nodules within leaflet cusps, particularly at leaflet bases and along the cusp hinge points; restricted leaflet opening; preserved commissures (unlike RHD)
Bicuspid valve: two unequal-sized cusps with a midline raphe (ridge from incomplete separation)
Leaflet calcification progressively reduces orifice area from normal (3-4 cm²) to critical stenosis (<1 cm²)

Hemodynamic Effects:

Pressure overload on left ventricle → compensatory CONCENTRIC hypertrophy
Increased LV wall tension and oxygen demand → angina (even without CAD)
Fixed outflow obstruction → reduced cardiac output → syncope with exertion
Eventually LV failure → pulmonary congestion → dyspnea → CHF
Post-stenotic aortic jet injury

Clinical Features:

The SAD triad: Syncope, Angina, Dyspnea (CHF) - in order of increasing severity
Harsh crescendo-decrescendo systolic ejection murmur at right upper sternal border; radiates to carotids
Pulsus parvus et tardus (weak, delayed carotid pulse)
Narrow pulse pressure
Natural history after symptoms: angina (5 yrs survival), syncope (3 yrs), CHF (2 yrs) → valve replacement is indicated

B. Rheumatic Mitral Stenosis (5 marks)

Etiology and Pathogenesis: Complication of rheumatic fever - an immune-mediated reaction following Group A beta-hemolytic Streptococcal pharyngitis. Molecular mimicry between streptococcal M-proteins and cardiac proteins (myosin, tropomyosin, valve glycoproteins) triggers cross-reactive T-cells and antibodies. The mitral valve is the most commonly and severely affected (100% in severe disease).

Pathology (Acute):

Aschoff bodies in myocardium: central fibrinoid necrosis surrounded by Anitschkow cells (macrophages with central ribbon-like "caterpillar" chromatin pattern) + lymphocytes + plasma cells
Endocarditis: small warty vegetations along the line of closure
McCallum's patch: area of endocardial thickening on posterior left atrial wall

Pathology (Chronic):

Fibrous thickening and scarring of leaflets
Commissural fusion (the two leaflet edges scar together → fused commisures)
Chordal shortening, thickening and fusion
Calcification in long-standing disease
The "fish mouth" or "buttonhole" appearance of the mitral valve orifice on gross examination

Hemodynamic Effects:

Obstruction to left atrial emptying → left atrial hypertension
Left atrial enlargement → pulmonary venous hypertension
Pulmonary edema and pulmonary hypertension
Eventually right ventricular pressure overload and right heart failure
Volume overload causes dilation, not hypertrophy (volume overload pattern)

Clinical Features:

Dyspnea, orthopnea, pulmonary edema
Atrial fibrillation (from left atrial dilation) → palpitations, stroke risk
Malar flush (mitral facies) - pink-red cheeks from chronic low cardiac output
Loud S1, opening snap (OS), low-pitched mid-diastolic rumble at apex
Risk of left atrial mural thrombus → systemic embolism (stroke)

C. Infective Endocarditis (5 marks)

Etiology: Microbial infection of heart valves or mural endocardium producing vegetations. Classification:

Acute IE: virulent organisms (S. aureus) on normal OR abnormal valves; rapidly destructive
Subacute IE: low-virulence organisms (S. viridans) almost always on pre-existing valve disease; indolent

Common Organisms:

S. viridans: 50-60% of native valve IE (from oral flora; dental procedures)
S. aureus: most overall; IV drug users (tricuspid); rapidly destructive
HACEK group: slow-growing oral flora; often culture-negative initially
Enterococcus: GI/GU procedures
Fungi (Candida): immunocompromised, prolonged IV lines

Pathology:

Vegetations: bulky, irregular, friable masses composed of fibrin + platelets + bacteria + inflammatory cells; on atrial surface of AV valves or ventricular surface of semilunar valves
Underlying leaflet: ulceration, perforation, abscess formation (ring abscess = infection erodes into the valve annulus)
Healing: fibrosis and calcification of affected cusps

Hemodynamic Effects:

Destruction of leaflet → acute regurgitation → acute volume overload → sudden CHF
Ring abscess → extension into conduction system → heart block
Large vegetations → obstruction (stenosis)

Clinical Features:

Systemic: fever (most constant finding), rigors, malaise, weight loss
New or changing heart murmur
Peripheral manifestations:
- Osler nodes (painful fingertip nodules - immune complex vasculitis)
- Janeway lesions (painless palmar/plantar macules - septic emboli)
- Roth spots (retinal hemorrhages with pale center)
- Splinter hemorrhages (subungual)
- Petechiae
Embolic complications: stroke (left-sided); septic pulmonary emboli (right-sided in IVDU)
Immune complex glomerulonephritis → hematuria, proteinuria

LAQ 3 — Cardiomyopathies & Congenital Heart Disease

"Classify the cardiomyopathies. Describe the pathogenesis, morphology, and clinical features of hypertrophic cardiomyopathy (HCM) in detail. Additionally, briefly describe Eisenmenger syndrome and its significance." (15 marks)

Model Answer:

Classification of Cardiomyopathies (2 marks)

Primary (heart muscle disease without other cause):

Dilated cardiomyopathy (DCM) - dilation + systolic failure
Hypertrophic cardiomyopathy (HCM) - hypertrophy + diastolic failure
Restrictive cardiomyopathy (RCM) - stiffness + diastolic failure
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) - fibrofatty RV replacement

Secondary: Amyloidosis, sarcoidosis, hemochromatosis, radiation, drugs (doxorubicin), alcoholic, peripartum

HCM - Pathogenesis (3 marks)

HCM is caused by autosomal dominant mutations in genes encoding SARCOMERIC PROTEINS - the actual contraction machinery of the heart cell. The two most commonly mutated genes are:

MYH7 (beta-myosin heavy chain) - most common
MYBPC3 (myosin binding protein C) - most common in some populations
Others: TNNT2 (troponin T), TNNI3 (troponin I), MYL2 (myosin light chain)

These mutations cause abnormal force generation, abnormal calcium handling, and trigger compensatory hypertrophy, but the hypertrophied cells are arranged chaotically (disarray) and cannot relax normally. The result is marked diastolic dysfunction (impaired relaxation and filling) with preserved or even hyperdynamic systolic function.

In approximately 25% of patients, dynamic left ventricular outflow tract obstruction (LVOTO) occurs due to:

Asymmetric hypertrophy of the interventricular septum
The Venturi effect during rapid systolic ejection draws the anterior mitral valve leaflet toward the hypertrophied septum - "Systolic Anterior Motion" (SAM)
This worsens obstruction and mitral regurgitation

HCM - Morphology (4 marks)

Gross:

Disproportionate (asymmetric) hypertrophy of the ventricular septum relative to the free wall - ratio >1.3:1 (asymmetric septal hypertrophy, ASH)
Heart weight grossly increased (can reach 500-800 g)
Left ventricular cavity is small (hypertrophied walls crowd the lumen)
Left atrial dilation (from diastolic dysfunction and MR)
Fibrous endocardial plaque on the anterior mitral leaflet (where it contacts the hypertrophied septum during SAM)

Microscopic (pathognomonic findings):

MYOCYTE DISARRAY: myofibers arranged in a chaotic, haphazard pattern instead of the normal parallel rows - THIS IS PATHOGNOMONIC OF HCM
Extreme cellular hypertrophy with enlarged, bizarre-shaped nuclei
Interstitial fibrosis (especially around intramural coronary arteries)
Intramural coronary artery narrowing (wall thickening without luminal plaque) - contributes to demand ischemia

HCM - Clinical Features (3 marks)

Often asymptomatic; discovered on family screening or incidentally
Most common cause of sudden cardiac death in young athletes (<35 years) - caused by ventricular fibrillation triggered by exertion-induced ischemia + arrhythmia
Exertional dyspnea (diastolic dysfunction - ventricle can't fill; most common symptom)
Angina (demand ischemia from hypertrophy)
Syncope (LVOTO reduces cardiac output)

Murmur characteristics:

Harsh systolic ejection murmur (LVOTO)
Murmur increases with reduced preload (Valsalva maneuver, standing, dehydration) because less blood in the ventricle worsens the obstruction
Murmur decreases with increased preload (squatting, lying down, leg raise) - more blood in the ventricle pushes the mitral leaflet away from the septum
This is the OPPOSITE of aortic stenosis, which does not change with these maneuvers

ECG: Left ventricular hypertrophy pattern; deep Q waves in lateral leads (from septal hypertrophy); Wolf-Parkinson-White (WPW) pattern in some

Management: Beta-blockers or calcium channel blockers (reduce heart rate → more diastolic filling time); avoid vigorous exercise; ICD implantation for high-risk patients; septal myectomy or alcohol septal ablation for severe LVOTO

Eisenmenger Syndrome (3 marks)

Definition: The reversal of a previously left-to-right cardiac shunt to a right-to-left shunt, secondary to pulmonary arterial hypertension that develops as a complication of the chronic increased pulmonary blood flow.

Mechanism:

Large left-to-right shunt (VSD, ASD, PDA) → chronic pulmonary overcirculation
Pulmonary vascular bed responds to increased flow and pressure → medial hypertrophy + intimal fibrosis of pulmonary arterioles → progressively elevated pulmonary vascular resistance
When pulmonary artery pressure equals or exceeds systemic pressure → right ventricular pressure rises above left ventricular pressure
Shunt reverses from LEFT-to-RIGHT → RIGHT-to-LEFT
Deoxygenated blood now enters the systemic circulation → CYANOSIS, clubbing, polycythemia

Significance:

Once Eisenmenger syndrome is established, surgical repair of the underlying defect is CONTRAINDICATED - the pulmonary vascular disease is irreversible and repair would eliminate the only available right-heart outlet
The condition progresses to right heart failure and premature death
Prevention requires early surgical correction of large shunts before pulmonary vascular disease develops
Pregnancy is extremely high-risk (maternal mortality 30-50%) in Eisenmenger syndrome

RAPID EXAM SELF-CHECK

Before your exam, make sure you can answer these from memory:

Four defects of Tetralogy of Fallot? (PS + VSD + Overriding aorta + RVH)
Peak MI rupture risk - which day? (Day 3-7)
Most common organism in IV drug user IE? (S. aureus - right sided, tricuspid)
Hallmark cell of rheumatic heart disease? (Anitschkow/caterpillar cell in Aschoff body)
Pathognomonic finding in HCM? (Myocyte disarray)
What replaces RV muscle in ARVC? (Fibrofatty tissue)
First microscopic change in MI? (Wavy fiber change at ~6 hours)
Beck's triad? (Hypotension + muffled heart sounds + elevated JVP)
What makes HCM murmur louder? (Valsalva/standing - less preload)
Eisenmenger - can you still operate? (NO - irreversible pulmonary hypertension)

Based on Robbins & Kumar Basic Pathology and Robbins, Cotran & Kumar Pathologic Basis of Disease | Aligned to KMT/QP-07/COL Weeks 6-7 curriculum

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