Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 1091: Bacterial endocarditis can cause all of the following except:

A. Cerebral infarct
B. Focal glomerulonephritis
C. Meningitis
D. Subcutaneous nodules (Correct Answer)

Explanation: **Explanation:** In Infective Endocarditis (IE), clinical manifestations arise from four mechanisms: continuous bacteremia, valvular destruction, septic embolization, and circulating immune complexes [1]. **Why "Subcutaneous nodules" is the correct answer:** Subcutaneous nodules are characteristic of **Acute Rheumatic Fever** (Jones Criteria), not IE [2]. In IE, the classic skin findings are **Osler nodes** (tender, pea-sized nodules on finger/toe pads due to immune complex deposition) and **Janeway lesions** (non-tender, erythematous macules on palms/soles due to septic emboli). While both involve the skin, "subcutaneous nodules" is a specific clinical term reserved for Rheumatic Fever. **Analysis of incorrect options:** * **Cerebral Infarct:** This is the most common CNS complication of IE, occurring when vegetative fragments break off (septic emboli) and occlude cerebral arteries [1], [3]. * **Focal Glomerulonephritis:** IE often triggers an immune-mediated response. Deposition of antigen-antibody complexes in the kidney leads to "flea-bitten kidney" appearance, clinically manifesting as focal or diffuse glomerulonephritis and hematuria [1]. * **Meningitis:** Continuous bacteremia or septic emboli can seed the meninges, leading to purulent or aseptic meningitis. **NEET-PG High-Yield Pearls:** * **Most common cause (Native Valve):** *Staphylococcus aureus* (Acute), *Viridans streptococci* (Subacute) [4]. * **Most common cause (IV Drug Users):** *Staphylococcus aureus* (Tricuspid valve involvement) [4]. * **Roth Spots:** Retinal hemorrhages with central clearing (Immune-mediated). * **Duke’s Criteria:** The gold standard for diagnosis (Major: Positive blood cultures and Echo evidence) [3].

Question 1092: Which of the following can cause a soft first heart sound (S1)?

A. Long standing severe mitral stenosis
B. Obesity
C. Mitral regurgitation
D. All of the above (Correct Answer)

Explanation: ### Explanation The **first heart sound (S1)** is primarily produced by the closure of the atrioventricular (AV) valves—the Mitral (M1) and Tricuspid (T1) valves—at the onset of ventricular systole. The intensity of S1 depends on the mobility of the leaflets, the distance they travel to close, and the rate of ventricular pressure rise. **Why "All of the Above" is Correct:** * **Long-standing severe Mitral Stenosis (MS):** While early MS typically presents with a *loud* S1 (due to high atrial pressure keeping leaflets wide apart) [1], **long-standing severe MS** leads to heavy calcification and fibrosis of the leaflets. This rigidity prevents them from vibrating or snapping shut effectively, resulting in a soft or muffled S1 [3]. * **Obesity:** This is an "extracardiac" cause. Increased chest wall thickness acts as an acoustic dampener, reducing the transmission of sound from the heart to the stethoscope, thereby softening all heart sounds, including S1. * **Mitral Regurgitation (MR):** In chronic MR, the mitral leaflets often fail to coapt properly or are structurally damaged [2]. Additionally, the rate of pressure rise ($dP/dt$) may be altered, and the lack of a "tight seal" during closure leads to a diminished S1. **High-Yield Clinical Pearls for NEET-PG:** 1. **Loud S1:** Seen in **Short PR interval** (leaflets are wide open at the start of systole), **Mild-to-Moderate MS** (pliable leaflets) [1], and **Hyperdynamic states** (tachycardia, exercise, anemia). 2. **Soft S1:** Seen in **Long PR interval (1st-degree heart block)** (leaflets float back together before systole), **Severe Calcific MS** [3], **MR**, and **Reduced myocardial contractility** (e.g., Heart Failure, Acute MI). 3. **Variable S1:** A classic sign of **Atrial Fibrillation** and **Complete Heart Block** (AV dissociation). 4. **Lungs:** Emphysema/COPD also cause a soft S1 due to increased air between the heart and the chest wall.

Question 1093: A patient post myocardial infarction develops atrial fibrillation. Subsequently, echocardiography shows a mural thrombus. What is the recommended management?

A. Warfarin (Correct Answer)
B. Cardioversion
C. Digoxin
D. Propranolol

Explanation: **Explanation:** The development of **Atrial Fibrillation (AF)** and a **mural thrombus** following a Myocardial Infarction (MI) significantly increases the risk of systemic thromboembolism (e.g., ischemic stroke). The primary goal of management in this scenario is systemic anticoagulation. **Why Warfarin is correct:** In the setting of a documented mural thrombus (usually occurring in the left ventricle post-anterior MI) [1] or AF, anticoagulation is mandatory to prevent embolization. **Warfarin** (Vitamin K Antagonist) is the traditional choice for long-term anticoagulation in these patients [2]. Current guidelines recommend anticoagulation for 3–6 months for mural thrombi to allow for thrombus resolution and endothelialization. **Why other options are incorrect:** * **Cardioversion:** While rhythm control is a strategy for AF, performing cardioversion in a patient with a known thrombus is contraindicated without prior therapeutic anticoagulation, as it may dislodge the clot and cause a stroke. * **Digoxin:** This is a rate-control agent. While it may be used for AF, it does not address the life-threatening risk of the mural thrombus. * **Propranolol:** This is a beta-blocker used for rate control and post-MI mortality benefit. However, like Digoxin, it has no effect on the thrombus itself. **High-Yield Clinical Pearls for NEET-PG:** * **Mural Thrombus:** Most common after a large **Anterior Wall MI** involving the apex [1]. * **Diagnosis:** Transthoracic Echocardiography (TTE) is the initial test; Cardiac MRI is the gold standard for detection [1]. * **Triple Therapy:** Patients post-MI with a stent who also require Warfarin (for AF/thrombus) are often put on "triple therapy" (Aspirin + Clopidogrel + Anticoagulant), though the duration is kept short to minimize bleeding risk. * **DOACs:** While Warfarin is the classic answer, newer guidelines also consider Direct Oral Anticoagulants (DOACs) as alternatives for LV thrombi.

Question 1094: Constrictive pericarditis is associated with each of the following except?

A. Radiation therapy for Hodgkin's disease
B. Tuberculosis
C. Bacterial (purulent) pericarditis
D. Hypothyroidism (Correct Answer)

Explanation: **Explanation:** **Constrictive Pericarditis (CP)** is the result of chronic inflammation leading to a thickened, fibrotic, and often calcified pericardium that restricts diastolic filling [1]. **Why Hypothyroidism is the Correct Answer:** Hypothyroidism is typically associated with **Pericardial Effusion** (often "gold-paint" appearance due to high cholesterol content), but it does **not** cause the chronic fibrosis or scarring required to produce Constrictive Pericarditis. While the effusion can rarely lead to tamponade, it does not progress to constriction. **Analysis of Incorrect Options:** * **Tuberculosis (B):** Historically and globally, TB remains the **most common cause** of constrictive pericarditis, especially in developing countries like India [1]. It causes a "cold" chronic inflammation that leads to heavy calcification [1]. * **Radiation Therapy (A):** Mediastinal radiation (commonly for Hodgkin’s lymphoma or breast cancer) is a major cause of CP in developed nations. It triggers progressive pericardial fibrosis years after exposure. * **Bacterial/Purulent Pericarditis (C):** Acute pyogenic infections (e.g., Staphylococcal or Pneumococcal) can lead to rapid thickening and organization of the pericardium, resulting in "subacute" constriction. **NEET-PG High-Yield Pearls:** 1. **Clinical Sign:** Look for **Kussmaul’s Sign** (paradoxical rise in JVP during inspiration) and a **Pericardial Knock** (early diastolic sound). 2. **Imaging:** Chest X-ray may show a "rim of calcification" around the heart. CT/MRI showing pericardial thickness **>3mm** is diagnostic. 3. **Hemodynamics:** Characterized by the **"Square Root Sign"** (dip-and-plateau) on ventricular pressure tracings. 4. **Treatment:** The definitive treatment is **Surgical Pericardiectomy** [1].

Question 1095: All are true about hypertrophic obstructive cardiomyopathy except?

A. Asymmetrical septal hypertrophy
B. Systolic ventricular dysfunction is absent
C. Anterior leaflet movement is delayed (Correct Answer)
D. Cardiac output is diminished

Explanation: Explanation: Hypertrophic Obstructive Cardiomyopathy (HOCM) is a genetic disorder characterized by primary myocardial hypertrophy, typically involving the interventricular septum [1]. Why Option C is the correct answer (The "Except"): In HOCM, the hallmark echocardiographic finding is **Systolic Anterior Motion (SAM)** of the mitral valve. This movement is **not delayed**; rather, it occurs **early in systole**. As blood is ejected through a narrowed outflow tract at high velocity (Venturi effect), the anterior leaflet of the mitral valve is "sucked" toward the hypertrophied septum. This leads to Left Ventricular Outflow Tract (LVOT) obstruction and concomitant mitral regurgitation. Analysis of other options: * **Option A:** Asymmetrical Septal Hypertrophy (ASH) is the classic anatomical feature, where the septum is significantly thicker than the posterior wall (Ratio >1.3:1). * **Option B:** HOCM is primarily a disease of **diastolic dysfunction** (impaired relaxation). Systolic function (Ejection Fraction) is typically preserved or even supranormal until the very end stages of the disease. * **Option D:** Due to the dynamic LVOT obstruction and impaired diastolic filling, the stroke volume and subsequent cardiac output are often diminished, especially during exertion [1]. High-Yield Clinical Pearls for NEET-PG: * **Murmur Dynamics:** The harsh systolic murmur of HOCM **increases** with maneuvers that decrease preload (Valsalva, Standing) and **decreases** with maneuvers that increase preload or afterload (Squatting, Handgrip). * **ECG Findings:** Look for "Dagger-like" Q waves in lateral leads (I, aVL, V5-V6). * **Histology:** Characterized by **myocyte disarray** [1]. * **Drug of Choice:** Beta-blockers (to improve diastolic filling time); avoid Nitrates and Diuretics as they worsen the obstruction.

Question 1096: A patient with an atrial septal defect (ASD) presents with a murmur similar to mitral regurgitation and left axis deviation of 40 degrees. What is the likely diagnosis?

A. Transposition of the great arteries (TGA)
B. Ostium secundum
C. Ostium primum
D. Floppy mitral valve (Correct Answer)

Explanation: ### Explanation The correct answer is **Floppy mitral valve (Mitral Valve Prolapse)**. #### 1. Why the correct answer is right In the context of an Atrial Septal Defect (ASD), the presence of a murmur resembling mitral regurgitation (MR) and **Left Axis Deviation (LAD)** is a classic triad. While Ostium primum ASD is the most common congenital cause of LAD, it typically presents with an axis of **-30° to -90°**. In this specific question, the axis is **-40°** (Left Axis Deviation) and the murmur is similar to MR. **Floppy Mitral Valve (Mitral Valve Prolapse)** is frequently associated with Secundum ASD (found in up to 37% of cases). The combination of a Secundum ASD (which usually has Right Axis Deviation) with a concurrent Floppy Mitral Valve can result in a shift toward Left Axis Deviation and a pansystolic or late systolic murmur of MR [1]. #### 2. Why the incorrect options are wrong * **Ostium secundum:** This is the most common type of ASD. It typically presents with **Right Axis Deviation (RAD)** and Right Bundle Branch Block (RBBB) on ECG. It does not cause an MR-like murmur unless associated with MVP [2]. * **Ostium primum:** While this causes LAD and MR (due to a cleft mitral valve), the LAD is usually more extreme (superior axis). However, in many standard NEET-PG patterns, if "Floppy Mitral Valve" is an option alongside ASD symptoms, it specifically tests the known association between Secundum ASD and MVP. * **Transposition of the great arteries (TGA):** This is a cyanotic heart disease presenting with neonatal cyanosis and an "egg-on-a-string" appearance on X-ray, not a simple ASD-MR clinical picture. #### 3. High-Yield Clinical Pearls for NEET-PG * **Ostium Secundum ASD:** Most common; associated with **RAD** and RBBB. * **Ostium Primum ASD:** Associated with **LAD**, RBBB, and Cleft Mitral Valve [2]; common in Down Syndrome. * **Sinus Venosus ASD:** Associated with Partial Anomalous Pulmonary Venous Connection (PAPVC). * **Lutembacher Syndrome:** Combination of ASD and acquired Mitral Stenosis. * **Holt-Oram Syndrome:** ASD + Thumb/Radial abnormalities ("Heart-Hand Syndrome").

Question 1097: What is the most common cause of right ventricular failure?

A. Cor pulmonale
B. Pulmonary involvement
C. Endomyocardial fibrosis
D. Left ventricular failure (Correct Answer)

Explanation: The most common cause of right ventricular (RV) failure is **Left Ventricular (LV) Failure**. [1] **Why Left Ventricular Failure is Correct:** The cardiovascular system operates in a closed circuit. When the left ventricle fails, it cannot effectively pump blood into the systemic circulation, leading to an increase in left ventricular end-diastolic pressure (LVEDP). [1] This pressure is transmitted backward into the left atrium and then into the pulmonary veins and capillaries. The resulting **pulmonary venous hypertension** increases the afterload on the right ventricle. Over time, the RV—which is a thin-walled chamber designed for low-pressure systems—succumbs to this chronic pressure overload, leading to hypertrophy and eventual failure. [1] **Analysis of Incorrect Options:** * **Cor Pulmonale:** This refers to RV enlargement/failure secondary to pulmonary hypertension caused by primary lung disease (e.g., COPD). While it is a significant cause of right-sided heart failure, it is statistically less common than failure secondary to LV dysfunction. * **Pulmonary Involvement:** Conditions like pulmonary embolism or interstitial lung disease can cause RV strain, but they are categorized under specific etiologies rather than being the "most common" overall cause. * **Endomyocardial Fibrosis:** This is a restrictive cardiomyopathy. While it can cause right-sided heart failure (especially in tropical regions), it is a rare clinical entity compared to the prevalence of left-sided heart disease. **High-Yield Clinical Pearls for NEET-PG:** * **Isolated RV Failure:** The most common cause of *isolated* RV failure (without LV involvement) is **Pulmonary Hypertension** or **Right Ventricular Infarction**. * **Clinical Sign:** The most sensitive clinical sign of RV failure is an elevated **Jugular Venous Pressure (JVP)**. [2] * **Bernheim Effect:** This refers to a paradoxical situation where LV enlargement causes the interventricular septum to bulge into the RV, causing RV outflow obstruction.

Question 1098: What is Wenckebach phenomenon?

A. Progressive lengthening of the PR interval until a QRS complex is dropped (Correct Answer)
B. Slurred QRS complex
C. Irregular heart rate and premature ventricular beats
D. Shortened ST intervals

Explanation: **Explanation:** **Wenckebach phenomenon**, also known as **Mobitz Type I Second-Degree AV Block**, is a conduction abnormality typically occurring at the level of the AV node [1]. The hallmark of this condition is a progressive delay in AV conduction in each successive beat, which manifests on an ECG as **progressive lengthening of the PR interval** [1]. Eventually, an atrial impulse fails to conduct to the ventricles, resulting in a **dropped QRS complex** [1]. Following the dropped beat, the AV node recovers, the PR interval resets to its shortest duration, and the cycle repeats [1]. **Analysis of Options:** * **Option A (Correct):** Accurately describes the classic ECG pattern of Mobitz Type I block. * **Option B (Incorrect):** A slurred QRS complex (specifically the "delta wave") is characteristic of **Wolff-Parkinson-White (WPW) syndrome**, caused by pre-excitation via an accessory pathway [2]. * **Option C (Incorrect):** While Wenckebach results in an "irregularly irregular" rhythm (grouped beating), it is defined by conduction failure, not premature ventricular beats (PVCs). * **Option D (Incorrect):** Shortened ST/QT intervals are typically associated with **hypercalcemia** or digoxin effect, not AV nodal conduction delays. **Clinical Pearls for NEET-PG:** * **Site of Block:** Usually the **AV Node** (proximal to the Bundle of His) [1]. * **Prognosis:** Generally benign and often asymptomatic; frequently seen in athletes or during sleep due to high vagal tone [1]. * **Vagal Maneuvers:** Carotid sinus massage usually **worsens** Mobitz Type I (by slowing AV conduction) but may improve Mobitz Type II. * **Management:** Usually requires no treatment unless the patient is symptomatic (bradycardia), in which case Atropine is the first-line drug. Permanent pacemakers are rarely indicated.

Question 1099: The following ECG represents?

A. Rabbit ear pattern
B. Delta wave
C. P pulmonale
D. P mitrale (Correct Answer)

Explanation: ***P mitrale*** - Characterized by **broad, notched or bifid P waves** (>0.12 seconds) in lead II, indicating **left atrial enlargement**. - The **bifid appearance** results from delayed activation of the enlarged left atrium, creating the characteristic "M-shaped" P wave. *Rabbit ear pattern* - This refers to the **RSR' pattern** seen in **right bundle branch block (RBBB)** in leads V1-V2. - It involves **QRS complexes**, not P waves, and appears as two distinct peaks resembling rabbit ears. *Delta wave* - A **slurred upstroke** of the QRS complex seen in **Wolff-Parkinson-White (WPW) syndrome**. - Results from **pre-excitation** via an accessory pathway, causing early ventricular depolarization, not P wave abnormalities. *P pulmonale* - Indicates **right atrial enlargement** with **tall, peaked P waves** (>2.5 mm) in leads II, III, and aVF. - Associated with conditions like **COPD** and **pulmonary hypertension**, appearing narrow and pointed rather than broad and notched.

Question 1100: Comment on the diagnosis from the ECG shown below?

A. RCA occlusion by thrombus (Correct Answer)
B. LAD occlusion by thrombus
C. LCX occlusion by thrombus
D. Infarct

Explanation: ***RCA occlusion by thrombus*** - **ST elevation** in **inferior leads (II, III, aVF)** is the classic ECG pattern for **right coronary artery (RCA)** occlusion. - The RCA typically supplies the **inferior wall** of the left ventricle and often the **posterior wall**, making this the most likely culprit vessel. *LAD occlusion by thrombus* - LAD occlusion would show **ST elevation** in **anterior leads (V1-V6)** and possibly **lead I and aVL**. - This pattern represents **anterior wall MI**, not the inferior wall changes seen in this ECG. *LCX occlusion by thrombus* - LCX occlusion typically causes **ST elevation** in **lateral leads (I, aVL, V5-V6)** or **posterior changes**. - May show **reciprocal ST depression** in anterior leads rather than the inferior lead changes observed. *Infarct* - While technically correct that an infarct is occurring, this option lacks **anatomical specificity**. - Fails to identify the **culprit vessel** or **location of infarct**, which is crucial for **treatment planning** and **prognosis**.

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