Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 1041: A 26-year-old man attends an occupational health assessment. A 12-lead ECG is recorded. He is feeling well and has no symptoms or significant past medical history. Based on the ECG findings, what is the most likely diagnosis?

A. Right Bundle Branch Block
B. Wolff-Parkinson White Syndrome (Correct Answer)
C. Brugada Syndrome
D. Normal Variant

Explanation: ***Wolff-Parkinson White Syndrome*** - Classic **ECG triad** includes **short PR interval** (<120ms), **delta wave** (slurred upstroke of QRS), and **wide QRS complex** (>120ms) due to ventricular pre-excitation via an **accessory pathway**. - Often discovered **incidentally** in asymptomatic young individuals during routine screening, as the **accessory pathway** allows early ventricular activation bypassing the normal AV node conduction delay. *Right Bundle Branch Block* - Characterized by **wide QRS** (>120ms) with **RSR' pattern** in V1-V2 and **wide S waves** in leads I and V6, but **no delta wave** present. - Maintains **normal PR interval** and lacks the characteristic **slurred upstroke** seen in pre-excitation syndromes. *Brugada Syndrome* - Distinguished by **coved ST elevation** in leads V1-V2 with **downsloping ST segments**, not delta waves or short PR intervals. - Associated with **sodium channel mutations** and risk of **ventricular arrhythmias**, but ECG shows normal PR interval and narrow QRS when not in arrhythmia. *Normal Variant* - Would show **normal PR interval** (120-200ms), **narrow QRS complex** (<120ms), and **absence of delta waves**. - Lacks any of the characteristic pre-excitation findings that suggest an **accessory pathway** or conduction abnormality.

Question 1042: Which of the following investigations can detect the volume of infarcted area in acute myocardial infarction?

A. Echocardiography (Correct Answer)
B. Electrocardiography
C. Levels of Creatine Phosphokinase-MB
D. Thallium scan

Explanation: The correct answer is **Echocardiography (Option A)**. In the setting of acute myocardial infarction (AMI), Echocardiography is the most practical bedside tool to assess the **volume and extent of the infarcted area** [1]. It detects regional wall motion abnormalities (RWMA) that occur almost immediately after coronary occlusion. By visualizing which segments of the myocardium are hypokinetic, akinetic, or dyskinetic, clinicians can estimate the "area at risk" and the total volume of functional loss. **Why other options are incorrect:** * **Electrocardiography (ECG):** While ECG is the gold standard for initial diagnosis and localization (e.g., Anterior vs. Inferior), it reflects electrical changes rather than physical volume [2]. It cannot precisely quantify the cubic volume of infarcted tissue. * **CPK-MB:** Cardiac enzymes correlate with the *magnitude* of myocardial necrosis, but they provide a biochemical estimate rather than a spatial or volumetric measurement of the infarct. * **Thallium Scan:** Thallium-201 is a "cold spot" scan used primarily for assessing myocardial viability and perfusion. While it can show areas of decreased uptake, it is rarely used in the *acute* phase to measure infarct volume due to its logistical complexity compared to Echo. **NEET-PG High-Yield Pearls:** * **Echo in AMI:** The earliest sign of ischemia on Echo is systolic wall thinning and reduced inward motion (RWMA) [1]. * **Gold Standard:** While Echo is the practical choice, **Cardiac MRI (Delayed Gadolinium Enhancement)** is the most accurate "Gold Standard" for quantifying infarct size and transmurality [3]. * **Negative Predictive Value:** A normal Echocardiogram during active chest pain has a very high negative predictive value for ruling out a large MI.

Question 1043: A 14-year-old boy was brought in a collapsed state with a history of 2 episodes of vomiting and presented with a feeble pulse and cold, clammy limbs. ECG is provided. What is the diagnosis?

A. Hypokalemia
B. Hyperkalemia (Correct Answer)
C. Hypocalcemia
D. Hypomagnesemia

Explanation: ***Hyperkalemia*** - ECG findings of **peaked T-waves**, **widened QRS complexes**, and **absent P-waves** are pathognomonic for severe hyperkalemia. - The clinical presentation of **cardiovascular collapse** with feeble pulse and cold, clammy limbs indicates life-threatening hyperkalemia causing cardiac conduction abnormalities. *Hypokalemia* - ECG would show **U-waves**, **flat or inverted T-waves**, and **prolonged QT interval**, not peaked T-waves. - Clinical presentation would include **muscle weakness** and **cramping**, not the acute cardiovascular collapse seen here. *Hypocalcemia* - ECG characteristic is **prolonged QT interval** due to delayed ventricular repolarization, not peaked T-waves. - Clinical features include **tetany**, **Chvostek's sign**, and **Trousseau's sign**, not cardiovascular collapse. *Hypomagnesemia* - ECG shows **torsades de pointes** and **prolonged QT interval**, similar to hypocalcemia findings. - Often associated with **concurrent hypokalemia** and **hypocalcemia**, presenting with neuromuscular irritability rather than cardiac collapse.

Question 1044: Brugada syndrome is associated with which of the following ECG findings?

A. Left Bundle Branch Block
B. Left Anterior Fascicular block
C. Left Posterior Fascicular block
D. Right Bundle Branch Block (Correct Answer)

Explanation: **Explanation:** **Brugada Syndrome** is an autosomal dominant genetic channelopathy, most commonly involving a mutation in the **SCN5A gene** (sodium channel). It is a leading cause of sudden cardiac death in young individuals with structurally normal hearts, particularly those of Southeast Asian descent. **Why the correct answer is right:** The hallmark of Brugada syndrome is a characteristic ECG pattern in the right precordial leads (V1–V3). This pattern consists of a **pseudo-Right Bundle Branch Block (RBBB)** morphology and ST-segment elevation. The "RBBB-like" pattern occurs because the sodium channel dysfunction primarily affects the right ventricular outflow tract (RVOT), leading to delayed depolarization and altered repolarization in that specific region, mimicking the terminal R' wave seen in a true RBBB. **Why the incorrect options are wrong:** * **Options A, B, and C:** Left Bundle Branch Block (LBBB), Left Anterior Fascicular Block (LAFB), and Left Posterior Fascicular Block (LPFB) involve conduction delays in the left ventricle. Brugada syndrome specifically targets the **Right Ventricle**, making these left-sided conduction abnormalities irrelevant to its diagnostic ECG criteria. **High-Yield Clinical Pearls for NEET-PG:** * **ECG Types:** * **Type 1 (Diagnostic):** "Coved" ST-elevation >2mm followed by an inverted T-wave in V1-V3. * **Type 2:** "Saddle-back" ST-elevation. * **Triggers:** Fever, alcohol, and certain drugs (e.g., sodium channel blockers) can unmask the ECG pattern. * **Management:** The only proven treatment to prevent sudden cardiac death is an **Implantable Cardioverter Defibrillator (ICD)**. * **Classic Presentation:** A young male with a history of syncope or nocturnal agonal respiration. Note: While the provided references discuss related conditions like Hypertrophic Cardiomyopathy, Long QT, and WPW, they do not specifically detail the pathophysiology or diagnostic criteria for Brugada Syndrome.

Question 1045: All of the following can occur in rheumatic fever except?

A. Mitral regurgitation
B. Mitral stenosis
C. Pericarditis
D. Loud first heart sound (Correct Answer)

Explanation: **Explanation:** The correct answer is **Loud first heart sound (S1)** because, in the **acute phase** of Rheumatic Fever (RF), the S1 is typically **soft or muffled**, not loud. **1. Why "Loud S1" is the correct choice (The Exception):** Acute Rheumatic Fever causes **pancarditis** [1]. Inflammation of the myocardium (myocarditis) leads to a prolonged PR interval (First-degree AV block). A prolonged PR interval allows the mitral valve leaflets to float back toward a semi-closed position before ventricular systole begins, resulting in a **soft S1**. Additionally, acute mitral regurgitation (common in RF) [2] further softens the S1. A *loud* S1 is a hallmark of chronic, calcified Mitral Stenosis, not the acute inflammatory phase of RF. **2. Analysis of Incorrect Options:** * **Mitral Regurgitation (MR):** This is the **most common** valvular abnormality in acute rheumatic carditis [2]. It occurs due to annular dilatation or chordal inflammation, presenting as a pansystolic murmur at the apex. * **Mitral Stenosis (MS):** While MS is a **chronic** sequela of rheumatic heart disease (occurring years later), the question asks what *can* occur in rheumatic fever (encompassing the disease spectrum). However, in the acute phase, a "Carey Coombs murmur" (a mid-diastolic murmur) can mimic MS due to valvulitis. * **Pericarditis:** As part of the **pancarditis** (endocarditis, myocarditis, and pericarditis) [1], patients can develop pericardial friction rubs or effusions. **Clinical Pearls for NEET-PG:** * **Most common valve involved:** Mitral > Aortic > Tricuspid > Pulmonary. * **Carey Coombs Murmur:** A short, mid-diastolic murmur heard in acute RF due to mitral valve leaflet edema (distinguish from the opening snap of chronic MS). * **Jones Criteria:** Remember that Carditis is a **Major** criterion, while a prolonged PR interval is a **Minor** criterion.

Question 1046: Which of the following statements regarding rheumatic heart disease is false?

A. May cause congestive heart failure
B. The pulmonary valve is most commonly affected (Correct Answer)
C. Affects young people
D. A varying degree of pancarditis is observed

Explanation: **Explanation:** **1. Why Option B is the correct (false) statement:** In Rheumatic Heart Disease (RHD), the **Mitral Valve** is the most commonly affected valve (involved in nearly all cases), followed by the Aortic valve. The **Pulmonary valve** is the **least commonly affected** valve in RHD. The order of frequency of valvular involvement is: **Mitral > Aortic > Tricuspid > Pulmonary.** **2. Analysis of incorrect options:** * **Option A (True):** RHD can lead to congestive heart failure (CHF) through two mechanisms: acute fulminant myocarditis during the initial rheumatic fever episode or chronic valvular dysfunction (like Mitral Stenosis or Aortic Regurgitation) leading to volume/pressure overload. * **Option C (True):** Acute Rheumatic Fever primarily affects children and young adults (peak age 5–15 years). The resulting chronic heart disease often manifests in young adulthood, making it a leading cause of cardiovascular morbidity in young people in developing countries. * **Option D (True):** Acute Rheumatic Fever is characterized by **pancarditis**, involving the endocardium (valvulitis), myocardium (Aschoff bodies), and pericardium (bread-and-butter pericarditis). **High-Yield Clinical Pearls for NEET-PG:** * **Most common lesion:** Mitral Regurgitation (MR) is the most common finding in *acute* carditis; Mitral Stenosis (MS) is the most common *chronic* manifestation. * **Pathognomonic feature:** **Aschoff bodies** (granulomatous lesions) in the myocardium are pathognomonic for RHD. * **Anitschkow cells:** These are "caterpillar cells" (enlarged macrophages) found within Aschoff bodies. * **Jones Criteria:** Used for diagnosis (2 Major OR 1 Major + 2 Minor criteria + evidence of preceding Strep infection).

Question 1047: A 70-year-old male with a history of hypertension and diabetes mellitus presents with the following rhythm, accompanied by a blood pressure of 90/40 mm Hg and a feeble pulse. What is the next step in management?

A. IV adenosine
B. IV diltiazem
C. DC cardioversion (Correct Answer)
D. Ibutilide

Explanation: ***DC cardioversion*** - The patient presents with **hemodynamic instability** (BP 90/40 mmHg, feeble pulse) requiring **immediate electrical cardioversion** per ACLS guidelines. - **Synchronized DC cardioversion** is the first-line treatment for any **hemodynamically unstable tachyarrhythmia** regardless of rhythm type. *IV adenosine* - **Adenosine** is used for stable patients with **narrow-complex SVT** and requires hemodynamic stability for safe administration. - In **hemodynamically unstable** patients, pharmacological agents delay definitive treatment and can worsen hypotension. *IV diltiazem* - **Diltiazem** is a calcium channel blocker used for **rate control** in stable atrial fibrillation or atrial flutter. - It can cause **further hypotension** and is contraindicated in hemodynamically unstable patients. *Ibutilide* - **Ibutilide** is used for **chemical cardioversion** of atrial fibrillation/flutter in hemodynamically stable patients. - It requires **continuous cardiac monitoring** and is inappropriate when immediate intervention is needed for instability.

Question 1048: A patient with myocardial infarction presents with nausea, vomiting, epigastric pain, and bradycardia. ECG shows a first-degree heart block. What is the most commonly involved coronary artery in this scenario?

A. Left anterior descending artery
B. Right coronary artery (Correct Answer)
C. Oblique artery
D. Left circumflex coronary artery

Explanation: **Explanation:** The clinical presentation described—nausea, vomiting, epigastric pain, bradycardia, and heart block—is classic for an **Inferior Wall Myocardial Infarction (IWMI)**. **1. Why the Right Coronary Artery (RCA) is correct:** * **Anatomy:** In approximately 80–85% of individuals (right-dominant circulation), the RCA gives off the posterior descending artery, which supplies the inferior wall of the left ventricle. * **Conduction System:** The RCA supplies the **SA node** (in 60% of cases) and the **AV node** (in 90% of cases). Ischemia to the RCA often leads to bradyarrhythmias and AV blocks (like the first-degree block mentioned) [3]. * **Bezold-Jarisch Reflex:** Ischemia of the inferior wall stimulates vagal afferent fibers, leading to the "Vagal Triad" of hypotension, bradycardia, and nausea/vomiting [2]. **2. Why the other options are incorrect:** * **Left Anterior Descending (LAD):** Supplies the anterior wall and septum. LAD infarcts typically present with tachycardia (due to sympathetic surge) and bundle branch blocks, rather than bradycardia. * **Left Circumflex (LCx):** Supplies the lateral wall. While it can supply the inferior wall in "left-dominant" individuals (10%), it is statistically less common than the RCA [1]. * **Oblique Artery:** This is a small branch (e.g., the oblique vein of Marshall or small atrial branches) and is not a major epicardial vessel responsible for MI. **High-Yield Clinical Pearls for NEET-PG:** * **Right Ventricular MI:** Always suspect this in IWMI patients with hypotension and clear lungs. **Avoid Nitrates** in these patients as they are preload-dependent. * **ECG Leads:** Inferior wall MI is seen in leads **II, III, and aVF** [1]. * **Autonomic Association:** Inferior MI = Parasympathetic (Vagal) signs; Anterior MI = Sympathetic signs [2].

Question 1049: Which of the following is NOT true about Hypertrophic Obstructive Cardiomyopathy?

A. Beta-2 agonists are useful (Correct Answer)
B. Asymmetrical hypertrophy of the septum
C. Dynamic left ventricular outflow obstruction
D. The condition improves on passive leg raising

Explanation: Hypertrophic Obstructive Cardiomyopathy (HOCM) is characterized by a dynamic pressure gradient in the Left Ventricular Outflow Tract (LVOT). The severity of this obstruction is inversely proportional to the **Left Ventricular (LV) volume**. Anything that decreases LV volume (decreased preload/afterload) or increases contractility will worsen the obstruction [1]. **Why Option A is the correct answer (False statement):** Beta-2 agonists (like Salbutamol) are **contraindicated** in HOCM. They cause peripheral vasodilation (decreasing afterload) and have mild positive inotropic effects. Both actions decrease the LV end-diastolic volume and increase the LVOT gradient, thereby worsening the obstruction and symptoms. **Analysis of other options:** * **Option B:** Asymmetrical Septal Hypertrophy (ASH) is the hallmark of HOCM, where the interventricular septum is significantly thicker than the posterior wall (Ratio >1.3:1) [1]. * **Option C:** The obstruction is "dynamic" because it varies with the cardiac cycle and loading conditions, often involving the **Systolic Anterior Motion (SAM)** of the mitral valve. * **Option D:** Passive leg raising increases venous return (preload). Increased LV volume pushes the septum away from the mitral valve, widening the LVOT and **improving** (decreasing) the murmur intensity. **High-Yield Clinical Pearls for NEET-PG:** 1. **Murmur Dynamics:** The HOCM murmur (harsh systolic) **increases** with Valsalva and standing (decreased preload) and **decreases** with Squatting and Handgrip (increased preload/afterload). 2. **Drug of Choice:** Beta-blockers (e.g., Metoprolol) are the first-line treatment as they increase diastolic filling time and decrease contractility. 3. **Avoid:** Nitrates, Diuretics, and ACE inhibitors, as they reduce preload/afterload and worsen the gradient [1].

Question 1050: What is the characteristic JVP finding in complete heart block?

A. Cannon a wave (Correct Answer)
B. Prominent x descent
C. Kussmaul sign
D. Slow y descent

Explanation: ### Explanation **Correct Option: A. Cannon a wave** In **Complete Heart Block (CHB)**, there is total atrioventricular (AV) dissociation. This means the atria and ventricles contract independently. Occasionally, the right atrium contracts against a **closed tricuspid valve** (because the ventricle is in systole). This sudden backflow of blood into the jugular vein produces a giant, intermittent surge known as a **"Cannon a wave."** **Analysis of Incorrect Options:** * **B. Prominent x descent:** This is typically seen in **Cardiac Tamponade**. In CHB, the x descent is often interrupted or obscured by the irregular atrial contractions. * **C. Kussmaul sign:** This refers to a paradoxical rise in JVP during inspiration, classically seen in **Constrictive Pericarditis** or Right Ventricular Infarction. It is not a feature of AV dissociation. * **D. Slow y descent:** A slow or delayed y descent indicates an obstruction to right ventricular filling, most commonly seen in **Tricuspid Stenosis** or Right Atrial Myxoma. **Clinical Pearls for NEET-PG:** * **Intermittent vs. Regular Cannon a waves:** Cannon a waves are **intermittent** in CHB and Ventricular Tachycardia (VT) with AV dissociation. They are **regular** in Junctional Rhythms or SVT (specifically AVNRT). * **Giant/Prominent a waves:** These occur when the right atrium contracts against a *stenosed* valve or a *non-compliant* ventricle (e.g., Tricuspid Stenosis, Pulmonary Hypertension, or Pulmonary Stenosis). * **Absent a waves:** Characteristically seen in **Atrial Fibrillation** due to the lack of organized atrial contraction. [1]

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Acute Coronary Syndromes

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Heart Failure

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Cardiac Arrhythmias

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Valvular Heart Diseases

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Cardiomyopathies

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Pericardial Diseases

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Congenital Heart Disease in Adults

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Hypertension and Hypertensive Emergencies

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Pulmonary Hypertension

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Cardiology — MCQs

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