Cardiology — MCQs

A 25-year-old male who is an IV drug user presents with a 3-week history of worsening lethargy and confusion. On examination, the pulse rate is 130 bpm and blood pressure is 120/80 mmHg. Cardiovascular examination reveals a raised JVP with large v-waves and a loud systolic murmur. A palpable, pulsatile liver is felt when the hepato-jugular reflex is attempted. What type of murmur is most fitting with this patient's presentation?

Q399Medium

What is the least common cause of endocarditis?

Q400Easy

The following ECG findings are seen in Hypokalemia:

Cardiology Indian Medical PG Practice Questions and MCQs

Question 391: Coronary heart disease may manifest as all, except?

A. Angina on effort
B. Cardiomyopathies (Correct Answer)
C. Myocardial infarction
D. Sudden death

Explanation: **Explanation:** Coronary Heart Disease (CHD) is primarily caused by atherosclerosis of the coronary arteries, leading to an imbalance between myocardial oxygen supply and demand [1]. The clinical manifestations of CHD are categorized under the umbrella of **Ischemic Heart Disease (IHD)**. **Why Cardiomyopathies is the Correct Answer:** Cardiomyopathies are defined as a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually exhibit inappropriate ventricular hypertrophy or dilatation. By definition, **primary cardiomyopathies** (e.g., Dilated, Hypertrophic, or Restrictive) are diseases of the heart muscle itself and are *not* caused by coronary artery disease, hypertension, or valvular disease [2]. While "Ischemic Cardiomyopathy" is a term often used clinically to describe heart failure due to CHD, it is technically a secondary consequence of ischemia, not a primary cardiomyopathy. **Analysis of Incorrect Options:** * **Angina on effort:** This is the classic presentation of Stable Ischemic Heart Disease, where fixed coronary stenosis limits blood flow during increased physical activity [1]. * **Myocardial infarction:** An Acute Coronary Syndrome (ACS) resulting from plaque rupture and thrombus formation, leading to myocardial necrosis [1]. * **Sudden death:** Often the first and only manifestation of CHD, usually occurring due to lethal arrhythmias (like Ventricular Fibrillation) secondary to acute ischemia [2]. **Clinical Pearls for NEET-PG:** * **Most common cause of CHD:** Atherosclerosis [1]. * **Silent Infarction:** Common in diabetics and elderly patients due to autonomic neuropathy. * **Gold Standard Investigation for CHD:** Coronary Angiography (CAG). * **Sudden Cardiac Death (SCD):** In young athletes, the most common cause is Hypertrophic Cardiomyopathy (HCM), but in adults over 35, the most common cause is CHD [2].

Question 392: Which of the following ECG findings is associated with acute myocardial infarction?

A. Elevation of S wave
B. Prolonged QT interval
C. Tall T waves with increased amplitude (Correct Answer)
D. Prolonged PR interval

Explanation: In acute myocardial infarction (AMI), the ECG undergoes a characteristic evolution [1]. The earliest change, often occurring within minutes of coronary occlusion, is the appearance of **Hyperacute T waves**. [3] ### Why Option C is Correct: Hyperacute T waves are characterized by increased amplitude (tall), a broad base, and symmetry. They represent the earliest stage of myocardial ischemia before ST-segment elevation occurs. This phenomenon is thought to be caused by localized extracellular hyperkalemia resulting from the breakdown of cell membranes in the ischemic zone [3]. ### Why Other Options are Incorrect: * **Option A (Elevation of S wave):** This is not a recognized ECG finding in AMI. In STEMI, we see **ST-segment elevation**, which is the elevation of the segment between the J-point and the beginning of the T wave, not the S wave itself [1], [2]. * **Option B (Prolonged QT interval):** While ischemia can sometimes prolong the QT interval, it is not a diagnostic hallmark of AMI. It is more commonly associated with electrolyte imbalances (hypocalcemia, hypomagnesemia) or drug toxicities. * **Option C (Prolonged PR interval):** This indicates a first-degree AV block. While an inferior wall MI can cause AV blocks due to ischemia of the AV node, it is a secondary complication rather than a primary diagnostic feature of the infarction itself. ### High-Yield Clinical Pearls for NEET-PG: * **ECG Evolution in STEMI:** Hyperacute T waves → ST-segment elevation (Pardee’s sign) → Q-wave formation → T-wave inversion [1]. * **Reciprocal Changes:** Look for ST-depression in leads opposite to the site of infarction (e.g., ST-depression in II, III, aVF if there is an Anterior MI) [1]. * **De Winter T waves:** A specific pattern (ST-depression with peaked T waves) indicating proximal LAD occlusion, considered a STEMI equivalent.

Question 393: Reversed splitting of the second heart sound is seen in all of the following conditions except?

A. Aortic stenosis
B. Left bundle branch block
C. Atrial septal defect (Correct Answer)
D. Systemic hypertension

Explanation: **Explanation:** The second heart sound (S2) is composed of two components: **A2 (Aortic)** and **P2 (Pulmonary)**. In a normal physiological state, A2 precedes P2, and the gap widens during inspiration [4]. **Reversed (paradoxical) splitting** occurs when A2 is significantly delayed, causing P2 to occur first. In this scenario, the split narrows or disappears during inspiration and widens during expiration. **Why Atrial Septal Defect (ASD) is the correct answer:** ASD is characterized by a **Fixed Wide Splitting** of S2, not reversed splitting [1]. In ASD, the continuous left-to-right shunt increases right ventricular stroke volume, delaying P2. Because the shunt equalizes pressure changes between the atria during the respiratory cycle, the split remains constant (fixed) regardless of inspiration or expiration [1], [2]. **Analysis of Incorrect Options (Causes of Reversed Splitting):** * **Aortic Stenosis:** Severe obstruction to the left ventricular outflow tract delays the closure of the aortic valve (A2), pushing it after P2 [3]. * **Left Bundle Branch Block (LBBB):** Delayed electrical activation of the left ventricle results in delayed mechanical contraction and late closure of the aortic valve. * **Systemic Hypertension:** High afterload in the systemic circulation can delay the closure of the aortic valve, leading to a paradoxical split. **High-Yield Clinical Pearls for NEET-PG:** * **Wide Variable Split:** Seen in Right Bundle Branch Block (RBBB) and Pulmonary Stenosis (P2 is delayed). * **Fixed Wide Split:** Pathognomonic for ASD. * **Paradoxical Split:** Think "Left-sided delays" (LBBB, AS, HOCM, Severe Hypertension). * **Single S2:** Seen in Tetralogy of Fallot (P2 is inaudible) or severe semilunar valve calcification.

Question 394: What is the median survival time in cardiac amyloidosis?

A. 1-3 months
B. 3-6 months
C. 6-12 months (Correct Answer)
D. 12-18 months

Explanation: **Explanation:** Cardiac amyloidosis, particularly the **AL (Light Chain) type**, is a restrictive cardiomyopathy characterized by the extracellular deposition of misfolded proteins [1]. The correct answer is **6-12 months** because, historically, AL amyloidosis with symptomatic heart failure carries an extremely poor prognosis. Once clinical signs of congestive heart failure appear, the disease progresses rapidly toward restrictive physiology and fatal arrhythmias. * **Why C is correct:** Large clinical cohorts and classic textbooks (like Harrison’s) cite a median survival of approximately **6 to 12 months** for untreated AL cardiac amyloidosis from the onset of heart failure. * **Why A & B are incorrect:** While the prognosis is dismal, a median survival of less than 6 months is typically reserved for patients in multi-organ shock or those with extremely high-stage biomarkers (NT-proBNP and Troponin) at the very end of the disease spectrum. * **Why D is incorrect:** A survival of 12-18 months or longer is more characteristic of **ATTR (Transthyretin)** amyloidosis, which has a more indolent course compared to the aggressive AL type. **High-Yield Clinical Pearls for NEET-PG:** 1. **ECG Paradox:** The hallmark is **low voltage QRS** complexes despite thick ventricular walls on Echocardiography (which shows a "speckled" or "granular" appearance). 2. **Gold Standard Diagnosis:** Endomyocardial biopsy showing **Apple-green birefringence** under polarized light with Congo Red stain. 3. **Cardiac MRI:** Characterized by **diffuse Late Gadolinium Enhancement (LGE)** in the subendocardial layer. 4. **Treatment:** While AL amyloidosis is treated with chemotherapy/bortezomib, **Tafamidis** is a specific stabilizer used for ATTR amyloidosis [1].

Question 395: Features of Hypertrophic Cardiomyopathy include all of the following except?

A. Asymmetric septal hypertrophy
B. Systolic anterior motion of the mitral valve (Correct Answer)
C. Dynamic left ventricular outflow obstruction
D. Pathophysiological systolic dysfunction

Explanation: **Explanation** Hypertrophic Cardiomyopathy (HCM) is primarily a **diastolic dysfunction** disorder characterized by a stiff, non-compliant left ventricle [1]. The hallmark of HCM is preserved or even enhanced systolic function (hyperdynamic circulation), with an ejection fraction often exceeding 70%. Therefore, **Option D (Pathophysiological systolic dysfunction)** is the correct answer as it is **not** a feature of HCM; systolic failure only occurs in the very late "burnt-out" phase of the disease. *Note: There appears to be a clerical error in the prompt's marking. Option B (SAM) is a classic feature of HCM, while Option D is the false statement.* **Analysis of Options:** * **A. Asymmetric Septal Hypertrophy (ASH):** This is the morphological hallmark [1]. The interventricular septum is disproportionately thicker than the posterior wall (Ratio >1.3:1). * **B. Systolic Anterior Motion (SAM):** Due to the Venturi effect created by high-velocity flow through a narrowed outflow tract, the anterior leaflet of the mitral valve is "sucked" toward the septum during systole, causing obstruction. * **C. Dynamic LVOT Obstruction:** Unlike aortic stenosis (fixed obstruction), the obstruction in HCM is dynamic. It worsens with factors that decrease preload (Valsalva, standing) or increase contractility. **NEET-PG High-Yield Pearls:** * **Inheritance:** Autosomal Dominant; most common mutation involves **Beta-myosin heavy chain** or Myosin-binding protein C [1]. * **Murmur:** Harsh systolic murmur at the left sternal border that **increases** with Valsalva/Standing and **decreases** with Squatting/Handgrip. * **ECG:** May show "dagger-like" Q waves in lateral leads (I, aVL, V5-V6). * **Management:** Beta-blockers are first-line (increase diastolic filling time). Avoid Nitrates and Diuretics as they worsen obstruction.

Question 396: A 60-year-old male with a known history of sarcoidosis is referred to the cardiology unit. Which of the following findings is involved in cardiac sarcoidosis?

A. First-degree heart block
B. Dilated cardiomyopathy
C. Echo features suggestive of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
D. All of the above (Correct Answer)

Explanation: **Explanation:** Cardiac sarcoidosis is a multi-system granulomatous disease characterized by the formation of non-caseating granulomas within the myocardium. These granulomas can involve any part of the heart, leading to a wide spectrum of clinical presentations. 1. **Conduction System Disease (Option A):** This is the most common manifestation. Granulomas frequently infiltrate the basal interventricular septum, affecting the AV node or Bundle of His. This leads to various degrees of heart block, ranging from **first-degree heart block** to complete heart block. 2. **Cardiomyopathy (Option B):** Extensive granulomatous infiltration and subsequent fibrosis lead to ventricular remodeling. While it may initially present as restrictive physiology, it frequently progresses to **Dilated Cardiomyopathy (DCM)** with reduced ejection fraction and congestive heart failure. 3. **ARVC Mimicry (Option C):** Sarcoidosis has a predilection for the right ventricle in some patients. Infiltration of the RV free wall can cause wall motion abnormalities, aneurysms, and fatty replacement that **mimic the echocardiographic and clinical features of ARVC**. **Clinical Pearls for NEET-PG:** * **Sudden Cardiac Death (SCD):** The most feared complication, usually due to ventricular arrhythmias or complete heart block. * **Gold Standard Diagnosis:** Endomyocardial biopsy (though sensitivity is low, ~20%, due to the patchy nature of the disease). * **Imaging of Choice:** **Cardiac MRI** (Late Gadolinium Enhancement) is highly sensitive; **PET scan** is used to assess active inflammation. * **Management:** Corticosteroids are the mainstay of treatment; ICD (Implantable Cardioverter Defibrillator) is often indicated for secondary prevention of SCD.

Question 397: Widely split S1 is heard in which of the following conditions?

A. Right bundle branch block (RBBB)
B. Mitral regurgitation (MR)
C. Atrial septal defect (ASD) (Correct Answer)
D. Ventricular septal defect (VSD)

Explanation: **Explanation:** The first heart sound (S1) is produced by the closure of the atrioventricular valves: the Mitral (M1) and Tricuspid (T1) valves. Normally, M1 precedes T1 by a very short interval, making S1 sound single. A **widely split S1** occurs when there is a significant delay in the closure of the tricuspid valve. **Why ASD is the Correct Answer:** In an Atrial Septal Defect (ASD), there is a chronic volume overload of the right atrium and right ventricle due to the left-to-right shunt [2]. This increased volume leads to a delay in the emptying of the right ventricle, which subsequently delays the closure of the tricuspid valve (T1) [1]. Furthermore, ASD is often associated with a Right Bundle Branch Block (RBBB) pattern, which further delays right ventricular depolarization and T1 closure. **Analysis of Incorrect Options:** * **RBBB:** While RBBB *can* cause a split S1, it is most classically associated with a **wide, fixed splitting of S2**. In the context of NEET-PG, if ASD is an option, it is the preferred answer for "wide splitting" as it involves both electrical delay and volume overload. * **Mitral Regurgitation (MR):** MR typically results in a **soft S1** because the mitral valve leaflets may not coapt properly or the pressure gradient between the LA and LV is altered. It does not cause wide splitting of S1. * **Ventricular Septal Defect (VSD):** VSD is primarily associated with a **wide splitting of S2** (due to prolonged RV ejection) and a pansystolic murmur, but it does not characteristically widen the S1 split. **Clinical Pearls for NEET-PG:** * **ASD Triad:** Wide fixed split S2, Mid-diastolic murmur (tricuspid flow), and S1 splitting [1]. * **Soft S1:** Seen in Mitral Regurgitation, First-degree Heart Block, and Severe Heart Failure. * **Loud S1:** Seen in Mitral Stenosis (pliable valve), Tachycardia, and Short PR interval. * **Reverse Splitting of S1:** Rare, seen in Left Bundle Branch Block (LBBB) or Mitral Stenosis.

Question 398: A 25-year-old male who is an IV drug user presents with a 3-week history of worsening lethargy and confusion. On examination, the pulse rate is 130 bpm and blood pressure is 120/80 mmHg. Cardiovascular examination reveals a raised JVP with large v-waves and a loud systolic murmur. A palpable, pulsatile liver is felt when the hepato-jugular reflex is attempted. What type of murmur is most fitting with this patient's presentation?

A. Functional murmur
B. Tricuspid stenosis
C. Pulmonary stenosis
D. Tricuspid regurgitation (Correct Answer)

Explanation: **Explanation:** The patient is a young IV drug user presenting with signs of right-sided heart failure, which strongly suggests **Infective Endocarditis (IE)**. In IV drug users, the **tricuspid valve** is the most commonly affected site (Staphylococcus aureus being the most frequent organism). **Why Tricuspid Regurgitation (TR) is correct:** The clinical triad of **raised JVP with prominent 'v' waves**, a **pansystolic murmur** (louder on inspiration), and a **pulsatile liver** is pathognomonic for TR [1]. The 'v' wave represents the filling of the right atrium against a closed tricuspid valve; in TR, the backflow of blood during ventricular systole exaggerates this wave [1]. This pressure is transmitted back through the IVC, causing the liver to pulsate synchronously with the heartbeat. **Why the other options are incorrect:** * **Functional murmur:** These are usually soft, mid-systolic, and not associated with structural pathology like a pulsatile liver or large v-waves. * **Tricuspid stenosis:** This would present with a mid-diastolic murmur [2] and a prominent **'a' wave** in the JVP (due to forceful atrial contraction), not a 'v' wave. * **Pulmonary stenosis:** This presents with an ejection systolic murmur and a prominent 'a' wave. It does not typically cause a pulsatile liver unless it leads to secondary TR. **NEET-PG High-Yield Pearls:** * **Carvallo’s Sign:** The murmur of TR increases in intensity during **inspiration** (due to increased venous return to the right heart). This distinguishes it from Mitral Regurgitation. * **IVDU & IE:** The most common valve involved is the Tricuspid valve; however, the most common cause of death in these patients is still left-sided heart failure. * **JVP in TR:** Characterized by a "giant v-wave" and a "steep y-descent" [1].

Question 399: What is the least common cause of endocarditis?

A. Atrial Septal Defect (ASD) (Correct Answer)
B. Patent Ductus Arteriosus (PDA)
C. Tetralogy of Fallot (TOF)
D. Ventricular Septal Defect (VSD)

Explanation: **Explanation:** The risk of **Infective Endocarditis (IE)** is primarily determined by the degree of **turbulence** in blood flow and the resulting pressure gradient across a cardiac lesion. High-velocity jets cause endothelial damage, leading to the deposition of fibrin and platelets (Non-Bacterial Thrombotic Endocarditis), which serves as a nidus for bacterial colonization. Diagnosis is typically made using the modified Duke criteria [3]. **Why ASD is the correct answer:** In a simple **Atrial Septal Defect (ostium secundum)**, the pressure gradient between the left and right atrium is very low [2]. This results in low-velocity, laminar flow across the defect rather than high-velocity turbulence. Consequently, the endocardium remains relatively undamaged, making IE extremely rare in isolated ASDs. **Analysis of incorrect options:** * **VSD (Option D):** This is a high-pressure gradient lesion (Left Ventricle to Right Ventricle). The high-velocity jet strikes the right ventricular wall, causing significant endothelial trauma and making it a high-risk site for IE [2]. * **PDA (Option B):** The continuous pressure gradient between the aorta and the pulmonary artery creates high turbulence, placing it at significant risk for IE. * **TOF (Option C):** Cyanotic heart diseases like Tetralogy of Fallot involve multiple structural abnormalities and turbulent flow, carrying a high risk for endocarditis. **Clinical Pearls for NEET-PG:** * **Highest Risk Lesions:** Prosthetic heart valves, previous IE, and cyanotic congenital heart disease (e.g., TOF) [1]. * **Moderate Risk Lesions:** VSD, PDA, Bicuspid aortic valve, and Mitral Valve Prolapse with regurgitation. * **Negligible Risk:** Isolated secundum ASD, 6 months post-repair of VSD/PDA (without residual shunt), and physiological murmurs. * **Prophylaxis Rule:** According to current AHA guidelines, antibiotic prophylaxis is **not** recommended for simple ASDs [1].

Question 400: The following ECG findings are seen in Hypokalemia:

A. Increased PR interval with ST depression (Correct Answer)
B. Increased PR interval with peaked T wave
C. Prolonged QT interval with T wave inversion
D. Decreased QT interval with ST depression

Explanation: Hypokalemia (Serum $K^+ < 3.5$ mEq/L) alters the resting membrane potential and prolongs the repolarization phase of the cardiac action potential. This leads to characteristic ECG changes that reflect delayed ventricular repolarization and increased myocardial excitability. [1] **Why Option A is Correct:** In hypokalemia, the ECG typically shows **ST-segment depression**, flattening or inversion of T waves, and the appearance of prominent **U waves**. As the deficiency worsens, the **PR interval increases** due to delayed conduction through the AV node [1]. The apparent prolongation of the QT interval is often actually a "QU interval" caused by the fusion of the T and U waves. **Analysis of Incorrect Options:** * **Option B:** Increased PR interval with **peaked T waves** is the hallmark of **Hyperkalemia**. Peaked "tented" T waves are the earliest sign of high potassium levels [1]. * **Option C:** While T wave inversion occurs in hypokalemia, the "prolonged QT" is usually a pseudo-prolongation (QU interval). True QT prolongation with T wave inversion is more characteristic of **Hypocalcemia** or myocardial ischemia. * **Option D:** **Decreased QT interval** (shortened QT) is a classic finding in **Hypercalcemia**, not hypokalemia. **High-Yield Clinical Pearls for NEET-PG:** * **Sequence of Hypokalemia ECG:** T-wave flattening $\rightarrow$ ST depression $\rightarrow$ Prominent U waves (best seen in V2-V4) $\rightarrow$ Prolonged PR interval. * **The "Rule of T and U":** In hypokalemia, as the T wave goes down, the U wave goes up. * **Severe Hypokalemia:** Can precipitate life-threatening arrhythmias like Torsades de Pointes, especially if the patient is on Digoxin (Hypokalemia increases Digoxin toxicity) [2]. * **Hypomagnesemia:** Often co-exists with hypokalemia and must be corrected to successfully treat the potassium deficit.

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Cardiology — MCQs

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