Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 1121: Which of the following is true about the third heart sound?

A. Present in constrictive pericarditis
B. Absent in aortic aneurysm
C. Absent in mitral stenosis (Correct Answer)
D. Present in cardiac tamponade

Explanation: The **Third Heart Sound (S3)**, also known as the ventricular gallop, occurs during the **early diastole** (rapid ventricular filling phase). It is caused by the sudden deceleration of blood flow into a dilated, compliant ventricle [3]. ### **Why Mitral Stenosis is the Correct Answer** For an S3 to occur, there must be a rapid, unimpeded flow of blood from the atrium into the ventricle. In **Mitral Stenosis**, the narrowed valve orifice acts as a physical barrier, obstructing the rapid filling phase [2]. Therefore, S3 is characteristically **absent** in significant mitral stenosis. If an S3 is heard in a patient with suspected mitral stenosis, it suggests the presence of concomitant mitral regurgitation or an alternative diagnosis [1]. ### **Analysis of Incorrect Options** * **A. Constrictive Pericarditis:** While a "Pericardial Knock" is the classic finding here, it is essentially an early, high-pitched S3 caused by the sudden cessation of ventricular filling by a rigid pericardium. * **B. Aortic Aneurysm:** An S3 is not directly related to an aneurysm itself, but if the aneurysm causes **Aortic Regurgitation**, the resulting volume overload of the left ventricle will frequently produce an S3. * **D. Cardiac Tamponade:** In tamponade, ventricular filling is restricted throughout diastole due to high intrapericardial pressure. Heart sounds are typically **muffled or distant**, and an S3 is generally not a feature of this condition. ### **High-Yield NEET-PG Pearls** * **Physiological S3:** Normal in children, young adults, and pregnancy. * **Pathological S3:** A hallmark of **Volume Overload** (e.g., Congestive Heart Failure, Mitral Regurgitation). * **Best heard:** At the apex with the **bell** of the stethoscope in the left lateral decubitus position [1]. * **S4 (Atrial Gallop):** Occurs in late diastole; characteristically absent in **Atrial Fibrillation** (due to lack of atrial contraction).

Question 1122: Which features favor constrictive pericarditis over restrictive cardiomyopathy?

A. Diastolic pressures are equalized and RV size is increased. (Correct Answer)
B. There is mild pericardial effusion.
C. Thickened pericardium is present and diastolic pressures are equalized.
D. Diastolic pressures are equalized and thickened pericardium is present.

Explanation: ### Explanation Distinguishing **Constrictive Pericarditis (CP)** from **Restrictive Cardiomyopathy (RCM)** is a classic NEET-PG challenge. Both present with heart failure symptoms and a "dip-and-plateau" (square root sign) on pressure tracings, but their pathophysiology differs. **Why Option A is Correct:** The hallmark of CP is **ventricular interdependence** within a fixed, rigid pericardial space. During inspiration, the decrease in intrathoracic pressure is not transmitted to the heart. As the right ventricle (RV) fills, the rigid pericardium forces the interventricular septum to bulge toward the left, leading to an **increase in RV size/filling** at the expense of the left ventricle. Furthermore, in CP, the **diastolic pressures** in all four chambers typically **equalize** (within 5 mmHg), whereas in RCM, the Left Ventricular End-Diastolic Pressure (LVEDP) is usually >5 mmHg higher than the RVEDP. **Analysis of Incorrect Options:** * **Option B:** Mild pericardial effusion is non-specific and can occur in various cardiac conditions; it does not define constriction. * **Options C & D:** While a **thickened pericardium** (>3-4 mm on CT/MRI) is a classic sign of CP [1], these options are less "complete" or specific than Option A in the context of hemodynamic differentiation. Many patients with CP have normal pericardial thickness (occult constriction), making ventricular interdependence (RV size changes) a more definitive physiological marker. Lateral or oblique X-ray projections may also be useful for detecting pericardial calcification in patients with CP [2]. ### NEET-PG High-Yield Pearls * **Kussmaul’s Sign:** Paradoxical rise in JVP on inspiration; seen in both, but more common in CP. * **Pericardial Knock:** High-pitched sound in early diastole; specific to CP. * **BNP Levels:** Typically **normal/low in CP** but **significantly elevated in RCM** (due to myocardial stretch). * **Imaging:** Cardiac MRI showing "septal bounce" or "shudder" confirms ventricular interdependence in CP.

Question 1123: Pulsatile liver and ascites are typically found in which condition?

A. Tricuspid regurgitation (Correct Answer)
B. Critical pulmonary stenosis
C. Mitral regurgitation
D. Mitral stenosis

Explanation: ### Explanation **Correct Answer: A. Tricuspid Regurgitation** The hallmark of **Tricuspid Regurgitation (TR)** is the backflow of blood from the right ventricle into the right atrium during systole [1]. This high-pressure systolic wave is transmitted retrograde into the superior and inferior vena cava. * **Pulsatile Liver:** The systolic surge reaches the hepatic veins, causing the liver to expand during systole (systolic hepatic pulsations) [1]. * **Ascites:** Chronic right-sided heart failure leads to increased systemic venous pressure and hepatic congestion, resulting in cardiac cirrhosis and transudative ascites [1]. **Why other options are incorrect:** * **B. Critical Pulmonary Stenosis:** While this causes right heart failure and a prominent 'a' wave in the JVP (due to forceful atrial contraction against a stiff ventricle), it does not typically cause a *systolic* pulsatile liver unless secondary TR develops. * **C. Mitral Regurgitation:** This affects the left side of the heart [2]. It leads to pulmonary congestion and "wet lungs." It only causes systemic venous signs in very late stages if it leads to secondary right heart failure. * **D. Mitral Stenosis:** This primarily causes left atrial enlargement and pulmonary hypertension. While it can eventually lead to right heart failure, the classic "pulsatile liver" is specific to the systolic regurgitant flow of TR [1]. **High-Yield Clinical Pearls for NEET-PG:** * **JVP in TR:** Characterized by a **giant 'v' wave** and a **steep 'y' descent** (Lancisi’s sign) [1]. * **Murmur:** A pansystolic murmur at the left lower sternal border that increases with inspiration (**Carvallo’s sign**) [1]. * **Differential for Pulsatile Liver:** Tricuspid Regurgitation (systolic), Constrictive Pericarditis (rarely), and Tricuspid Stenosis (presystolic). * **Ebstein’s Anomaly:** A common congenital cause of severe TR leading to these findings.

Question 1124: What is the most common cause of Left Ventricular Hypertrophy?

A. Hypertension (Correct Answer)
B. Aortic Stenosis
C. Aortic Regurgitation
D. Hypertrophic Obstructive Cardiomyopathy (HOCM)

Explanation: **Explanation:** **1. Why Hypertension is the Correct Answer:** Left Ventricular Hypertrophy (LVH) is a compensatory response to increased **afterload**. In systemic hypertension, the left ventricle must generate higher pressure to overcome the increased systemic vascular resistance [2]. According to **Laplace’s Law** (Wall Stress = Pressure × Radius / 2 × Wall Thickness), the myocardium undergoes **concentric hypertrophy** (addition of sarcomeres in parallel) to normalize wall stress. While several conditions cause LVH, hypertension is the most common cause in the general population due to its high global prevalence [1], [3]. **2. Analysis of Incorrect Options:** * **B. Aortic Stenosis:** This is a classic cause of pressure-overload LVH [2]. While it produces significant hypertrophy, it is far less common epidemiologically than systemic hypertension. * **C. Aortic Regurgitation:** This causes **volume overload**, leading to **eccentric hypertrophy** [2] (ventricular dilation with proportional wall thickening; sarcomeres added in series). It is not the most common cause of generalized LVH. * **D. Hypertrophic Obstructive Cardiomyopathy (HOCM):** This is a genetic disorder characterized by asymmetrical septal hypertrophy. It is a primary myocardial disease and is rare compared to secondary causes like hypertension. **3. Clinical Pearls for NEET-PG:** * **ECG Criteria:** The most common criteria used is the **Sokolow-Lyon Index** (S in V1 + R in V5 or V6 > 35 mm). * **Gold Standard Investigation:** Echocardiography (more sensitive than ECG). * **Concentric vs. Eccentric:** Pressure overload (HTN, AS) leads to concentric hypertrophy; Volume overload (AR, MR) leads to eccentric hypertrophy [2]. * **Reverse Remodeling:** ACE inhibitors and ARBs are the drugs of choice to help regress hypertensive LVH.

Question 1125: A 60-year-old woman presents with a murmur suggestive of mitral stenosis and an echocardiography confirmed a mass attached to the fossa ovalis of the left atrial septum. What is the most likely diagnosis?

A. Cardiac myxoma (Correct Answer)
B. Endocarditis
C. Lymphoma
D. Metastatic cancer to the heart

Explanation: ### Explanation **Correct Answer: A. Cardiac Myxoma** **Why it is correct:** Cardiac myxoma is the most common primary cardiac tumor in adults. Approximately **75-80% occur in the left atrium**, typically attached by a pedicle to the **interatrial septum at the fossa ovalis**. The clinical presentation often mimics **mitral stenosis** because the pedunculated mass can physically obstruct the mitral valve orifice during diastole (the "wrecking ball" effect) [3]. This produces a mid-diastolic murmur [1] and sometimes a characteristic "tumor plop" heard on auscultation [3]. **Why the other options are incorrect:** * **B. Endocarditis:** Usually presents with fever, new-onset regurgitant murmurs (not stenotic), and vegetations on valve leaflets rather than a large mass on the septum [2]. * **C. Lymphoma:** Primary cardiac lymphomas are extremely rare and typically involve the right heart or cause pericardial effusions rather than a septal mass mimicking mitral stenosis. * **D. Metastatic cancer:** While more common than primary tumors, metastases (e.g., from lung, breast, or melanoma) usually involve the pericardium or myocardium and rarely present as a solitary pedunculated mass on the fossa ovalis. **NEET-PG High-Yield Pearls:** * **Triad of Myxoma:** Constitutional symptoms (fever, weight loss due to IL-6 production), Embolic phenomena, and Obstructive symptoms (mimicking mitral stenosis). * **Position Dependency:** Symptoms and murmurs may change with the patient's body position. * **Carney Complex:** An autosomal dominant syndrome (PRKAR1A mutation) featuring atrial myxomas, skin pigmentation (lentigines), and endocrine overactivity. * **Diagnosis:** Echocardiography is the gold standard for initial identification [2].

Question 1126: Wide pulse pressure is seen in which of the following conditions?

A. Beri beri (Correct Answer)
B. Cardiac tamponade
C. Diarrhea
D. Aortic stenosis

Explanation: Pulse pressure is the difference between systolic (SBP) and diastolic blood pressure (DBP). A wide pulse pressure occurs when there is either an increase in stroke volume (elevated SBP) or a decrease in peripheral vascular resistance (lowered DBP) [1]. **Why Beriberi is Correct:** Wet Beriberi (Thiamine/Vitamin B1 deficiency) is a classic cause of high-output heart failure. It leads to systemic vasodilation and the formation of multiple small arteriovenous shunts. This significantly reduces peripheral vascular resistance (lowering DBP) and increases venous return, which boosts stroke volume (raising SBP). The result is a characteristically wide pulse pressure. **Why Incorrect Options are Wrong:** * **Cardiac Tamponade:** Causes a narrow pulse pressure [2]. Fluid in the pericardial sac restricts ventricular filling, leading to a sharp drop in stroke volume and SBP [2]. * **Diarrhea:** Leads to hypovolemia. Reduced blood volume decreases stroke volume and triggers compensatory vasoconstriction, resulting in a narrow pulse pressure. * **Aortic Stenosis:** Known for a "Pulsus Parvus et Tardus" (small and slow pulse). The narrowed valve orifice limits the stroke volume and slows the rate of ejection, leading to a narrow pulse pressure [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Other causes of Wide Pulse Pressure:** Aortic Regurgitation (most common cause), Thyrotoxicosis, Anemia, Fever, and Patent Ductus Arteriosus (PDA) [1]. * **Water-Hammer Pulse:** Often associated with wide pulse pressure conditions, particularly Aortic Regurgitation [1]. * **Narrow Pulse Pressure:** Seen in Heart Failure, Shock, and Mitral Stenosis.

Question 1127: Torsade de pointes is caused by:

A. Hypermagnesemia
B. Metabolic acidosis
C. Hypomagnesemia (Correct Answer)
D. Metabolic alkalosis

Explanation: **Explanation:** **Torsades de Pointes (TdP)** is a specific form of polymorphic ventricular tachycardia characterized by a "twisting of the points" around the isoelectric line. It occurs in the setting of a **prolonged QT interval** [1], [2]. **Why Hypomagnesemia is correct:** Magnesium acts as a natural calcium channel blocker and is essential for the function of the Na+/K+-ATPase pump. **Hypomagnesemia** (and hypokalemia) leads to impaired repolarization of cardiac myocytes, which prolongs the action potential duration and the QT interval [3]. This creates a substrate for **Early After-Depolarizations (EADs)**. When these EADs reach a threshold, they trigger the rapid, irregular firing characteristic of TdP. Consequently, intravenous Magnesium Sulfate is the first-line treatment for TdP, even in patients with normal serum magnesium levels. **Why the other options are incorrect:** * **Hypermagnesemia:** High magnesium levels actually stabilize the cardiac membrane and are used to *treat* arrhythmias; they do not cause TdP. * **Metabolic Acidosis/Alkalosis:** While severe pH imbalances can affect cardiac excitability, they are not primary or classic triggers for TdP. TdP is specifically linked to electrolyte disturbances (Hypo-K, Hypo-Mg, Hypo-Ca) and drugs that prolong the QT interval. **High-Yield Clinical Pearls for NEET-PG:** * **Drug-induced TdP (ABCDE):** **A**ntiarrhythmics (Class IA, III), **B**iotics (Macrolides, Fluoroquinolones), **C**isapride (Antipsychotics/Antiemetics), **D**epressants (TCAs), **E**lectrolytes (Hypo-K, Hypo-Mg). * **Congenital Long QT Syndromes:** Romano-Ward (Autosomal Dominant, pure cardiac) and Jervell and Lange-Nielsen (Autosomal Recessive, cardiac + sensorineural deafness) [2]. * **Management:** IV Magnesium Sulfate is the drug of choice. If refractory, use overdrive pacing or Isoproterenol to increase heart rate (which shortens the QT interval). Avoid Class IA and III antiarrhythmics.

Question 1128: Carvallo's sign is seen in which of the following conditions?

A. Tricuspid stenosis (Correct Answer)
B. Mitral stenosis
C. Aortic stenosis
D. Aortic regurgitation

Explanation: **Explanation:** **Carvallo’s sign** is a clinical finding characterized by the **augmentation of a systolic or diastolic murmur during inspiration**. It is a hallmark sign used to differentiate right-sided heart murmurs from left-sided ones. 1. **Why Tricuspid Stenosis is correct:** During inspiration, intrathoracic pressure decreases, leading to an increase in venous return to the right atrium and ventricle. In **Tricuspid Stenosis (TS)**, this increased blood flow across the narrowed tricuspid valve during diastole intensifies the mid-diastolic murmur [2]. While Carvallo’s sign is most classically associated with **Tricuspid Regurgitation (TR)** (systolic murmur), it is also characteristically positive in **Tricuspid Stenosis** (diastolic murmur), making it the correct choice among the options provided. 2. **Why other options are incorrect:** * **Mitral Stenosis (MS):** The murmur of MS is best heard at the apex and typically **decreases** or remains unchanged during inspiration because the increased pulmonary capacitance during inspiration slightly reduces blood flow to the left heart [2]. * **Aortic Stenosis (AS) & Aortic Regurgitation (AR):** These are left-sided lesions. Murmurs originating from the aortic valve generally decrease in intensity during inspiration and are better heard during **expiration** [1]. **High-Yield Clinical Pearls for NEET-PG:** * **The Rule:** All right-sided murmurs (Tricuspid/Pulmonary) increase with inspiration (Carvallo’s sign), EXCEPT the **Pulmonary Ejection Click** in Pulmonary Stenosis, which decreases. * **Rivero-Carvallo's Sign:** Specifically refers to the pansystolic murmur of TR increasing with inspiration. * **Differentiation:** Use inspiration to distinguish TR (increases) from MR (decreases/no change).

Question 1129: A double apical impulse is seen in which condition?

A. Hypertrophic Obstructive Cardiomyopathy (HOCM) (Correct Answer)
B. Cardiac tamponade
C. Aortic regurgitation
D. Pulmonary hypertension

Explanation: ### Explanation **Correct Answer: A. Hypertrophic Obstructive Cardiomyopathy (HOCM)** In HOCM, the double apical impulse (also known as a **bifid impulse**) occurs due to two distinct mechanical events felt during systole [2]: 1. **First Component:** The initial forceful contraction of the hypertrophied left ventricle. 2. **Second Component:** A sudden interruption of ventricular outflow caused by **Systolic Anterior Motion (SAM)** of the mitral valve against the thickened septum. This creates a "midsystolic dip," followed by a second pressure peak as the ventricle continues to contract against the obstruction. *Note: If a forceful atrial contraction (S4) is also palpable, it can result in a triple apical impulse.* **Why the other options are incorrect:** * **B. Cardiac Tamponade:** The apex beat is typically **faint or impalpable** due to the insulating effect of the surrounding pericardial fluid. * **C. Aortic Regurgitation:** Characterized by a **hyperdynamic (volume-overload)** apex beat that is displaced laterally and inferiorly, but it remains a single, forceful thrust [1] [3]. * **D. Pulmonary Hypertension:** This leads to right ventricular hypertrophy, which typically manifests as a **left parasternal heave**, not a double apical impulse [1]. **NEET-PG High-Yield Pearls for HOCM:** * **Triple Ripple:** A palpable S4 + Double Systolic Impulse (pathognomonic for HOCM) [2]. * **Pulse:** Characterized by **pulsus bisferiens** (a double-peaked arterial pulse). * **Murmur:** A harsh systolic ejection murmur that **increases** with Valsalva or standing (decreased preload) and **decreases** with squatting or handgrip (increased afterload/preload) [2]. * **ECG:** Often shows "dagger-like" Q waves in lateral leads (I, aVL, V5-V6).

Question 1130: An ankle-brachial index (ABI) that suggests increased risk of myocardial infarction would be:

A. <0.9 (Correct Answer)
B. <0.6
C. >0.9
D. >0.6

Explanation: The **Ankle-Brachial Index (ABI)** is a non-invasive tool used to screen for Peripheral Arterial Disease (PAD). It is calculated by dividing the higher systolic blood pressure at the ankle (tibialis posterior or dorsalis pedis) by the higher systolic blood pressure in the arm. **Why <0.9 is correct:** An **ABI <0.9** is the diagnostic threshold for PAD. [1] PAD is considered a "coronary artery disease equivalent." Because atherosclerosis is a systemic process, its presence in the lower extremities indicates widespread vascular damage. [1] Patients with an ABI <0.9 have a significantly higher risk of cardiovascular events, including myocardial infarction (MI) and stroke, regardless of whether they have symptoms of claudication. [1] **Analysis of Incorrect Options:** * **<0.6 (Option B):** While an ABI <0.6 indicates moderate-to-severe PAD and carries an even higher risk of MI, it is a subset of the standard diagnostic cutoff. * **>0.9 (Option C):** An ABI between **0.91 and 1.30** is considered normal. Values in this range indicate healthy blood flow and a lower risk of cardiovascular events. * **>0.6 (Option D):** This range includes normal values (0.9–1.3), which would not suggest an increased risk of MI. **High-Yield Clinical Pearls for NEET-PG:** * **ABI >1.4:** Suggests non-compressible, calcified vessels (commonly seen in **Diabetes Mellitus** and Chronic Kidney Disease). In such cases, a **Toe-Brachial Index (TBI)** should be performed. * **ABI 0.4–0.7:** Associated with moderate PAD and intermittent claudication. [1] * **ABI <0.4:** Associated with severe PAD, rest pain, and critical limb ischemia. [1] * **Gold Standard:** While ABI is the best screening tool, **Digital Subtraction Angiography (DSA)** remains the gold standard for anatomical mapping before intervention.

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Cardiology — MCQs

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