Cardiac Pathology — MCQs

Cardiac Pathology Indian Medical PG Practice Questions and MCQs

Question 61: What is the major histological feature of myocardial infarction?

A. Liquefactive necrosis
B. Fibrinoid necrosis
C. Coagulative necrosis (Correct Answer)
D. Contraction band necrosis

Explanation: **Explanation:** **1. Why Coagulative Necrosis is Correct:** Myocardial infarction (MI) is a form of ischemic cell death resulting from the sudden occlusion of a coronary artery [1]. In most solid organs (except the brain), ischemia leads to **coagulative necrosis**. This process is characterized by the denaturation of structural proteins and enzymes. The loss of enzymes prevents proteolysis, which "freezes" the cell's architecture in place for several days. Histologically, this is seen as "ghost-like" cells that retain their basic shape but lack nuclei (karyolysis) [1]. **2. Analysis of Incorrect Options:** * **Liquefactive Necrosis:** This is characteristic of ischemic injury in the **Central Nervous System (brain)** or in focal bacterial/fungal infections (abscesses) [3]. It involves complete digestion of dead cells, turning the tissue into a liquid viscous mass. * **Fibrinoid Necrosis:** This occurs in immune-mediated vascular damage (e.g., Polyarteritis Nodosa) or malignant hypertension. It is characterized by the deposition of immune complexes and fibrin in arterial walls. * **Contraction Band Necrosis:** While seen in MI, it is specifically a feature of **reperfusion injury**. It occurs when calcium enters damaged myocytes upon restoration of blood flow, causing hypercontraction of myofibrils [1]. It is not the "major" histological feature of the infarct itself. **3. NEET-PG High-Yield Pearls:** * **Earliest Histological Change (0–30 mins):** No change visible by light microscopy [1]. * **First 4–12 hours:** Wavy fibers (due to tugging by adjacent viable myocardium) [1]. * **12–24 hours:** Definitive coagulative necrosis begins, accompanied by neutrophilic infiltration [1]. * **Stain for Early Detection:** Triphenyltetrazolium chloride (TTC) stain—infarcted areas remain pale/white, while viable tissue turns brick red [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 552. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 552-554. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 148-149.

Question 62: Senile cardiac amyloidosis is due to deposition of amyloid which is similar to which of the following proteins?

A. Beta-2 microglobulin
B. Transthyretin (Correct Answer)
C. Atrial natriuretic peptide (ANP)
D. Pyrin

Explanation: **Explanation:** **Senile Systemic Amyloidosis (SSA)**, also known as Age-related Amyloidosis, occurs due to the deposition of **wild-type Transthyretin (TTR)** [1]. Transthyretin is a serum protein synthesized in the liver that normally functions to transport thyroxine and retinol [1]. In elderly individuals (typically >70 years), this protein can become unstable and misfold, depositing as amyloid fibrils predominantly in the ventricles of the heart [1]. This leads to restrictive cardiomyopathy, though it carries a better prognosis than AL amyloidosis [2]. **Analysis of Options:** * **Option A (Beta-2 microglobulin):** This protein forms **Aβ2M** amyloid. It is characteristically seen in patients on long-term **hemodialysis** because the protein is not effectively filtered by dialysis membranes, leading to deposits in joints and tendon sheaths (Carpal Tunnel Syndrome) [1]. * **Option C (Atrial Natriuretic Peptide):** Deposition of ANP leads to **Isolated Atrial Amyloidosis (IAA)** [2]. Unlike senile systemic amyloidosis which affects the ventricles, IAA is confined to the atria and is often an incidental finding in the elderly [2]. * **Option D (Pyrin):** Mutations in the *MEFV* gene (which encodes pyrin) cause **Familial Mediterranean Fever (FMF)** [5]. This leads to the deposition of **AA amyloid** (derived from Serum Amyloid-Associated protein), not TTR [5]. **High-Yield Pearls for NEET-PG:** 1. **TTR Mutations:** While wild-type TTR causes senile amyloidosis, **mutated TTR** causes Familial Amyloid Polyneuropathies/Cardiomyopathies [1]. 2. **Staining:** All amyloid shows **Apple-green birefringence** under polarized light after **Congo Red** staining [4]. 3. **Diagnosis:** Cardiac MRI (Late Gadolinium Enhancement) and Technetium-pyrophosphate (PYP) scans are modern diagnostic mainstays. 4. **Most common systemic amyloidosis:** AL Amyloidosis (Light chain), associated with Plasma Cell Dyscrasias [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, p. 266. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 580-581. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 266-267. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 268-269. [5] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 267-268.

Question 63: Which of the following is the most common tumor of the heart?

A. Myxoma (Correct Answer)
B. Lipoma
C. Rhabdomyoma
D. None of the above

Explanation: **Explanation:** The correct answer is **A. Myxoma**. In cardiac pathology, it is crucial to distinguish between primary and secondary tumors. While metastatic (secondary) tumors are the most common tumors found in the heart overall, **Myxoma** is the most common **primary** tumor of the heart in adults [1]. * **Myxoma:** These are benign mesenchymal tumors [1]. Approximately 75-90% occur in the **left atrium**, typically attached to the interatrial septum at the fossa ovalis via a stalk (pedunculated) [1], [2]. Clinically, they can cause a "wrecking ball" effect, damaging mitral valves or causing "ball-valve" obstruction, leading to sudden syncopal episodes [2]. * **Lipoma:** While these can occur in the heart (often in the left ventricle or right atrium), they are significantly less common than myxomas [1]. * **Rhabdomyoma:** This is the most common primary cardiac tumor in **infants and children** [1]. It is highly associated with **Tuberous Sclerosis** (TSC1/TSC2 mutations) and often presents as multiple gray-white myocardial masses that frequently regress spontaneously. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common heart tumor overall:** Metastatic tumors (most commonly from lung, breast, or melanoma). 2. **Most common primary heart tumor (Adults):** Myxoma [1]. 3. **Most common primary heart tumor (Children):** Rhabdomyoma [1]. 4. **Carney Complex:** A familial syndrome (PRKAR1A mutation) characterized by multiple cardiac myxomas, spotty skin pigmentation, and endocrine overactivity. 5. **Histology of Myxoma:** Features "Lepidic" cells (stellate or globular cells) embedded in an abundant acid mucopolysaccharide (myxoid) stroma [2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 304-306. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 583-584.

Question 64: What is the characteristic pathological finding in carcinoid of the heart?

A. Fibrous endocardial thickening of the right ventricle and tricuspid valve (Correct Answer)
B. Collagen deposition in the wall of the right ventricle and tricuspid valve
C. Interstitial fibrous thickening of the right ventricle and pulmonary valve
D. Mononuclear inflammatory infiltrate in the wall of the right atrium

Explanation: **Explanation:** **Carcinoid Heart Disease** is a manifestation of systemic carcinoid syndrome, occurring in approximately 50% of patients with metastatic neuroendocrine tumors (usually from the ileum). **Why Option A is Correct:** The hallmark of carcinoid heart disease is the formation of **pearly-white, plaque-like fibrous thickenings** on the endocardium [1]. These lesions are composed of smooth muscle cells and collagen fibers embedded in an acid mucopolysaccharide-rich matrix [1]. Crucially, these plaques affect the **right side of the heart** (right ventricle, tricuspid, and pulmonary valves) because the vasoactive substances (Serotonin, Bradykinin) are inactivated by the lungs (via monoamine oxidase) before they can reach the left heart. **Why the other options are incorrect:** * **Option B:** While collagen is present, the primary pathology is **endocardial thickening** (surface plaques) rather than infiltration into the muscular "wall" of the ventricle [1]. * **Option C:** The thickening is **endocardial**, not "interstitial." Interstitial fibrosis is more characteristic of conditions like chronic ischemia or myocarditis [1]. * **Option D:** Carcinoid heart disease is a non-inflammatory, chemical-induced fibrotic process. A mononuclear infiltrate would suggest an inflammatory condition like viral myocarditis. **High-Yield NEET-PG Pearls:** * **Location:** Right heart is involved. Left heart involvement is rare and suggests either a **patent foramen ovale (R-to-L shunt)** or a **primary bronchial carcinoid**. * **Valvular Lesions:** Typically causes **Tricuspid Insufficiency (Regurgitation)** and **Pulmonary Stenosis** [1]. * **Mediator:** **Serotonin (5-HT)** is the primary culprit. Urinary **5-HIAA** is the diagnostic marker. * **Morphology:** "Plaque-like" endocardial thickening is the classic buzzword [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 570-572.

Question 65: A 15-year-old boy died suddenly while playing in the field. On autopsy, fibrofatty replacement of the right ventricular myocardium is seen. What is the most likely diagnosis?

A. Arrhythmogenic right ventricular dysplasia (Correct Answer)
B. Dilated cardiomyopathy
C. Hypertrophic cardiomyopathy
D. Obstructive cardiomyopathy

Explanation: ### Explanation **Correct Answer: A. Arrhythmogenic Right Ventricular Dysplasia (ARVD)** **Why it is correct:** Arrhythmogenic Right Ventricular Dysplasia (also known as ARVC) is an autosomal dominant inherited heart muscle disease. The hallmark pathological feature is the **replacement of the right ventricular myocardium with fibrofatty tissue** [1]. This leads to thinning of the RV wall, electrical instability, and life-threatening ventricular arrhythmias. It is a classic cause of **sudden cardiac death (SCD)** in young athletes and adolescents, often triggered by physical exertion. **Why other options are incorrect:** * **B. Dilated Cardiomyopathy (DCM):** Characterized by four-chamber enlargement and impaired systolic function. Histology shows non-specific findings like myocyte hypertrophy and interstitial fibrosis, but not the specific fibrofatty replacement of the RV. * **C. Hypertrophic Cardiomyopathy (HCM):** The most common cause of SCD in young athletes [1]. However, the pathology involves massive ventricular hypertrophy (usually the septum) and **myocyte disarray**, not fibrofatty replacement [2]. * **D. Obstructive Cardiomyopathy:** This is typically a functional variant of HCM (HOCM) where the thickened septum obstructs the left ventricular outflow tract [2]. The pathological hallmark remains myocyte disarray. **NEET-PG High-Yield Pearls:** * **Genetic Mutation:** Most commonly involves mutations in **desmosomal proteins** (e.g., Plakoglobin, Desmoplakin, Plakophilin-2) [1]. * **Naxos Disease:** A specific triad of ARVD, palmoplantar keratoderma, and woolly hair (mutation in the *Plakoglobin* gene) [1]. * **Carvajal Syndrome:** Similar to Naxos but involves the Left Ventricle (mutation in the *Desmoplakin* gene). * **ECG Finding:** Look for the **Epsilon wave** (a small notch at the end of the QRS complex) in leads V1-V3. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 576-577. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 577-578.

Question 66: Which type of cardiomyopathy is characterized by contractile dysfunction?

A. Dilated (Correct Answer)
B. Restrictive
C. Hypertrophic
D. Infiltrative

Explanation: ### Explanation **1. Why Dilated Cardiomyopathy (DCM) is Correct:** Dilated cardiomyopathy is primarily a **systolic dysfunction** disorder [1]. The hallmark of DCM is progressive cardiac dilation and contractile (pump) failure. The heart becomes "flabby" and enlarged, leading to a significantly decreased **Ejection Fraction (EF <40%)** [1]. Because the ventricular walls are stretched and thin, the myocytes cannot generate sufficient force to eject blood, resulting in impaired contractility. **2. Why the Other Options are Incorrect:** * **Hypertrophic Cardiomyopathy (HCM):** This is characterized by massive myocardial hypertrophy and **diastolic dysfunction** [1]. The primary issue is a "stiff" left ventricle that cannot fill properly during diastole, but the contractile function (systolic function) is usually preserved or even hyperdynamic (high EF) [1]. * **Restrictive Cardiomyopathy (RCM):** Similar to HCM, RCM is a disorder of **diastolic filling** [1]. The ventricles are of normal size but are stiff and non-compliant, restricting filling. Contractile function remains relatively normal until late stages. * **Infiltrative Cardiomyopathy:** This is a sub-type of Restrictive Cardiomyopathy (e.g., Amyloidosis, Sarcoidosis). It causes stiffening of the myocardium, leading to **diastolic dysfunction**, not primary contractile failure [1]. **3. NEET-PG High-Yield Pearls:** * **Most Common Type:** DCM is the most common form of cardiomyopathy (90% of cases). * **Genetic Link:** Mutations in the **TTN gene (Titin)** are the most common genetic cause of DCM [1]. * **Morphology:** Look for "globular" heart enlargement and mural thrombi in the apex [1]. * **Microscopy:** Non-specific; features include myocyte hypertrophy and interstitial fibrosis [1]. * **Key Causes:** Alcohol, Beriberi (B1 deficiency), Coxsackie B virus, Doxorubicin, and Pregnancy (Peripartum) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 572-574.

Question 67: Which is the most sensitive and specific marker for myocardial infarction?

A. CK-MB
B. Troponin (Correct Answer)
C. Myoglobin
D. LDH

Explanation: **Explanation:** **Troponin (specifically Troponin I and T)** is the gold standard and the most sensitive and specific marker for myocardial infarction (MI). These proteins are components of the cardiac muscle contractile apparatus. Unlike other markers, cardiac-specific isoforms (cTnI and cTnT) are virtually absent in the blood of healthy individuals, making even minor elevations highly indicative of myocardial injury. They begin to rise within **3–12 hours**, peak at **24 hours**, and remain elevated for **7–10 days (cTnI)** or up to **14 days (cTnT)**. **Analysis of Incorrect Options:** * **CK-MB (Creatine Kinase-MB):** Previously the gold standard, it is less specific than Troponin because it can be elevated in skeletal muscle injury [1]. However, it is still useful for detecting **re-infarction** because it returns to baseline quickly (within 48–72 hours) [1]. * **Myoglobin:** This is the **earliest marker** to rise (within 1–2 hours). While highly sensitive for early detection, it is very non-specific as it is found in all muscle types; thus, a negative result is useful only to "rule out" MI early on. * **LDH (Lactate Dehydrogenase):** This is a late marker that peaks at 3–4 days [1]. It is no longer used in routine practice due to its lack of specificity (found in RBCs, liver, and muscle) [1], [2]. **High-Yield NEET-PG Pearls:** * **Earliest marker:** Myoglobin. * **Most specific marker:** Troponin I. * **Marker for Re-infarction:** CK-MB [1]. * **Marker that stays elevated longest:** Troponin T (up to 2 weeks). * **AST (Aspartate Aminotransferase):** Historically used but now obsolete for MI diagnosis [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 255-256. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 552-554.

Question 68: A 25-year-old basketball player suddenly collapsed during an athletic event and died. Autopsy revealed a hypertrophied septum. What is the most probable diagnosis?

A. Hypertrophic Obstructive Cardiomyopathy (HOCM) (Correct Answer)
B. Right ventricular conduction abnormality
C. Epilepsy
D. Snake bite

Explanation: **Explanation:** The clinical presentation of sudden cardiac death (SCD) in a young athlete during strenuous physical activity, combined with autopsy findings of a **hypertrophied septum**, is a classic description of **Hypertrophic Obstructive Cardiomyopathy (HOCM)** [1], [2]. **1. Why HOCM is correct:** HOCM is the most common cause of SCD in young athletes. It is an autosomal dominant disorder, most frequently caused by mutations in genes encoding sarcomeric proteins (e.g., **Beta-myosin heavy chain** or **Myosin-binding protein C**) [1]. Pathologically, it is characterized by **asymmetric septal hypertrophy** (disproportionate thickening of the interventricular septum compared to the left ventricular free wall) and **myocyte disarray** on histology [1]. Death usually occurs due to ventricular arrhythmias triggered by physical exertion [2]. **2. Why other options are incorrect:** * **Right ventricular conduction abnormality:** While conditions like Brugada Syndrome or ARVD can cause SCD, they do not typically present with isolated septal hypertrophy on autopsy. * **Epilepsy:** While seizures can cause collapse, they are rarely a cause of sudden death in an athlete and would not explain the cardiac anatomical findings. * **Snake bite:** This would present with local puncture marks, systemic envenomation signs (neurotoxicity/hemotoxicity), and a relevant history, rather than isolated septal hypertrophy. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Most common mutation involves the **Beta-myosin heavy chain**. * **Histology:** Look for **"Myocyte Disarray"** (disorganized bundles of myocytes) [1]. * **Clinical Sign:** A harsh systolic murmur that **increases** with Valsalva or standing (due to decreased preload) and **decreases** with squatting. * **Gross Pathology:** "Banana-shaped" left ventricular cavity due to septal bulging [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 576-578. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 303-304.

Question 69: A 30-year-old male patient presented with dyspnea. Echocardiography showed mitral stenosis with left atrial hypertrophy. The excised mitral valve is shown in the image. What is the most likely diagnosis given the findings?

A. Tuberculosis
B. Sarcoidosis
C. Rheumatic heart disease (Correct Answer)
D. Fungal granuloma

Explanation: ***Rheumatic heart disease*** - **Mitral stenosis** with **left atrial hypertrophy** in a young adult is pathognomonic of rheumatic heart disease, especially in endemic areas like India. - The excised valve shows characteristic **fish mouth deformity**, **commissural fusion**, **leaflet thickening**, and **subvalvular apparatus changes** typical of chronic rheumatic valvulitis. *Tuberculosis* - Tuberculosis rarely causes **isolated mitral stenosis** and typically presents with **pericardial involvement** or **constrictive pericarditis**. - **Granulomatous inflammation** with **caseous necrosis** would be evident histologically, which is not characteristic of mitral stenosis pathology. *Sarcoidosis* - Cardiac sarcoidosis primarily affects the **conduction system** and **ventricular myocardium**, rarely causing valvular stenosis. - Presents with **non-caseating granulomas** and typically involves **multiple organ systems** with **bilateral hilar lymphadenopathy**. *Fungal granuloma* - Fungal endocarditis typically causes **vegetative lesions** and **valve destruction** rather than the organized **fibrotic stenosis** seen in rheumatic disease. - Usually occurs in **immunocompromised patients** or those with **prosthetic valves**, and presents acutely rather than as chronic stenosis.

Question 70: Which of the following statements about Nonbacterial thrombotic endocarditis (NBTE) is false?

A. Characterized by the deposition of sterile thrombi on cardiac valves
B. The vegetations in NBTE are typically small (1 to 5 mm in diameter)
C. Valvular damage is a prerequisite for NBTE to occur (Correct Answer)
D. Hypercoagulable states are the usual precursor to NBTE

Explanation: Nonbacterial thrombotic endocarditis (NBTE), formerly known as marantic endocarditis, is characterized by the formation of sterile, non-infective vegetations on heart valves [1]. **Why Option C is the Correct (False) Statement:** Unlike infective endocarditis, which often requires a pre-existing valvular abnormality, **NBTE typically occurs on previously normal valves.** The primary driver is not structural damage, but rather a systemic hypercoagulable state or circulating cytokines that trigger fibrin and platelet deposition. **Analysis of Other Options:** * **Option A:** NBTE vegetations are **sterile** (composed of fibrin and platelets) and do not contain microorganisms, distinguishing them from infective endocarditis [1]. * **Option B:** The vegetations are characteristically **small (1–5 mm)**, single or multiple, and are loosely attached along the line of closure of the leaflets [1]. * **Option D:** **Hypercoagulable states** are the hallmark precursors. It is frequently associated with advanced malignancies (especially mucinous adenocarcinomas—known as **Trousseau syndrome**) and chronic wasting diseases. **High-Yield Clinical Pearls for NEET-PG:** * **Morphology:** Vegetations are friable and can easily embolize, leading to systemic infarcts (e.g., stroke). * **Valve Involvement:** Most commonly affects the **Mitral valve**, followed by the Aortic valve. * **Key Association:** Often seen in patients with **DIC** (Disseminated Intravascular Coagulation) or underlying malignancy. * **Comparison:** Unlike Libman-Sacks endocarditis (SLE), NBTE vegetations occur only on the valve surfaces and do not cause significant valvular inflammation or scarring [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 568.

Practice by Chapter

Congenital Heart Disease

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Ischemic Heart Disease

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Hypertensive Heart Disease

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Valvular Heart Disease

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Myocarditis and Cardiomyopathies

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Pericardial Disease

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Cardiac Tumors

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Heart Failure Pathophysiology

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Cardiac Transplantation Pathology

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Endocarditis

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