Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 711: Which of the following is effective in the management of patients with heart failure with preserved ejection fraction?

A. Digoxin
B. Angiotensin receptor blocker with neprilysin inhibitor (Correct Answer)
C. Isosorbide mononitrate
D. Phosphodiesterase inhibitor

Explanation: ### Explanation **Heart Failure with Preserved Ejection Fraction (HFpEF)**, defined by an LVEF ≥50%, is characterized by diastolic dysfunction and increased filling pressures. Unlike HFrEF, many traditional therapies have historically failed to show significant mortality benefits in HFpEF. **Why Option B is Correct:** **Angiotensin Receptor-Neprilysin Inhibitors (ARNI)**, such as Sacubitril/Valsartan, are now recommended for HFpEF management. The **PARAGON-HF trial** demonstrated that ARNI reduces the risk of total hospitalizations for heart failure, particularly in patients with an LVEF at the lower end of the "preserved" spectrum (45–57%) and in women. It works by inhibiting neprilysin (increasing natriuretic peptides) and blocking the RAAS pathway, thereby reducing fibrosis and improving myocardial relaxation. ARB therapy produces beneficial haemodynamic changes similar to ACE inhibitors and is a useful alternative [1]. **Why Other Options are Incorrect:** * **A. Digoxin:** While useful in HFrEF for rate control in atrial fibrillation [3], the **DIG-PEF trial** showed no significant reduction in hospitalizations or mortality in HFpEF patients. * **C. Isosorbide Mononitrate:** The **NEAT-HFpEF trial** showed that long-acting nitrates actually decreased physical activity levels and did not improve quality of life or exercise tolerance in these patients. * **D. Phosphodiesterase Inhibitors (e.g., Sildenafil):** The **RELAX trial** demonstrated that PDE-5 inhibitors do not improve exercise capacity or clinical status in HFpEF. **High-Yield Clinical Pearls for NEET-PG:** * **SGLT2 Inhibitors (Empagliflozin/Dapagliflozin):** Currently considered the **first-line therapy** for HFpEF (based on EMPEROR-Preserved and DELIVER trials) as they are the first drugs to show a definitive reduction in the composite of CV death and HF hospitalizations. * **MRA (Spironolactone):** Recommended to reduce hospitalizations (TOPCAT trial), especially in patients with elevated BNP. Brain natriuretic peptide (BNP) is elevated in heart failure and acts as a marker of risk [2]. * **Diagnosis:** Requires symptoms of HF, LVEF ≥50%, and evidence of diastolic dysfunction (via Echo or elevated BNP) [2].

Question 712: Which of the following valvular heart diseases is most commonly associated with sudden death?

A. Aortic Stenosis (Correct Answer)
B. Mitral Stenosis
C. Mitral Regurgitation
D. Aortic Regurgitation

Explanation: ### Explanation **Correct Answer: A. Aortic Stenosis (AS)** **Why Aortic Stenosis is the Correct Answer:** Aortic Stenosis is the valvular lesion most frequently associated with **sudden cardiac death (SCD)**, particularly when it becomes symptomatic [1]. The pathophysiology involves severe left ventricular outflow tract obstruction, leading to massive left ventricular hypertrophy (LVH). SCD in AS occurs due to: 1. **Ventricular Arrhythmias:** The hypertrophied myocardium is prone to ischemia (even with normal coronaries) and fibrosis, creating a substrate for fatal ventricular tachycardia or fibrillation [1]. 2. **Exercise-induced Hypotension:** During exertion, the fixed cardiac output cannot meet systemic demand [1]. This triggers a baroreceptor reflex leading to vasodilation and a catastrophic drop in perfusion pressure, resulting in syncope or cardiac arrest. **Why Other Options are Incorrect:** * **B. Mitral Stenosis:** Typically presents with features of pulmonary congestion (dyspnea) or atrial fibrillation [2]. While it can cause systemic embolism, it rarely causes sudden death. * **C & D. Mitral and Aortic Regurgitation:** These are "volume overload" states [2]. The heart compensates through eccentric hypertrophy over many years. While they eventually lead to heart failure, the risk of sudden, terminal arrhythmic events is significantly lower than the "pressure overload" state seen in AS. **High-Yield Clinical Pearls for NEET-PG:** * **The Classic Triad of AS:** Dyspnea (most common), Angina, and Syncope (**SAD** mnemonic). * **Survival after symptom onset:** Angina (5 years), Syncope (3 years), Dyspnea/HF (2 years). * **Physical Exam:** Pulsus parvus et tardus (slow-rising, low-amplitude pulse) and a harsh crescendo-decrescendo systolic murmur radiating to the carotids [1]. * **Key Contraindication:** Avoid Nitrates and ACE inhibitors in severe AS, as they can cause a precipitous drop in preload/afterload, leading to syncope.

Question 713: Which ECG finding is characteristic of hyperkalemia?

A. T wave inversion
B. ST depression
C. P pulmonale
D. Wide QRS complex (Correct Answer)

Explanation: **Explanation:** Hyperkalemia is a life-threatening electrolyte abnormality that affects cardiac conduction in a predictable, progressive sequence [1]. As serum potassium levels rise, the resting membrane potential of myocytes becomes less negative (partially depolarized), leading to decreased excitability and slower conduction velocity [1]. **Why the Correct Answer is Right:** The **Wide QRS complex** occurs due to slowed intraventricular conduction. As potassium levels continue to rise (typically >6.5–7.0 mEq/L), the depolarization phase (Phase 0) of the action potential is blunted, resulting in a widened QRS [1]. If left untreated, this can progress to a "sine wave" pattern, ventricular fibrillation, or asystole [1]. **Analysis of Incorrect Options:** * **A. T wave inversion:** Hyperkalemia typically causes **tall, peaked (tented) T waves** with a narrow base, not inversion [1]. T wave inversion is more common in ischemia or hypokalemia. * **B. ST depression:** While non-specific, ST depression is more characteristic of **hypokalemia** (often accompanied by U waves) or myocardial ischemia. * **C. P pulmonale:** This refers to tall, peaked P waves in lead II, which is a sign of **right atrial enlargement** (often due to chronic lung disease), not an electrolyte imbalance. In hyperkalemia, P waves actually flatten and eventually disappear [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Sequence of ECG changes:** Tall peaked T waves → Prolonged PR interval → Flattened/absent P waves → **Widened QRS** → Sine wave pattern [1]. * **Treatment Priority:** Intravenous **Calcium Gluconate** is the first-line treatment to stabilize the cardiac membrane (it does not lower potassium levels) [2]. * **"Pseudohyperkalemia":** Always consider hemolysis during blood collection if ECG is normal despite high lab values.

Question 714: A 40-year-old man with a history of intravenous drug abuse develops rapidly progressive right-sided heart failure. Which of the following conditions is the most likely cause?

A. Aortic insufficiency
B. Mitral regurgitation
C. Ruptured chordae tendineae
D. Tricuspid insufficiency (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Tricuspid insufficiency** **Why it is correct:** In the context of **Intravenous Drug Abuse (IVDA)**, the most common cardiac complication is **Infective Endocarditis (IE)**. Unlike the general population, IVDA patients frequently develop right-sided endocarditis because the tricuspid valve is the first "filter" encountered by contaminated needles/syringes injected into the venous system [2]. Acute **Tricuspid Insufficiency (Regurgitation)** leads to sudden volume overload of the right ventricle, manifesting as **rapidly progressive right-sided heart failure** (elevated JVP, hepatomegaly, and peripheral edema) [1]. *Staphylococcus aureus* is the most common causative organism in these cases. **Why the other options are incorrect:** * **A. Aortic insufficiency & B. Mitral regurgitation:** While these can occur in IVDA, they involve the left side of the heart. Left-sided failure typically presents with pulmonary congestion (dyspnea, crackles) rather than isolated right-sided failure [2]. * **C. Ruptured chordae tendineae:** This is a mechanical complication usually associated with the mitral valve (causing acute MR) or secondary to myocardial infarction [3]. While IE can cause chordae rupture, it is less specific to the IVDA/right-heart failure presentation than primary tricuspid valve involvement. **NEET-PG High-Yield Pearls:** * **Most common valve involved in IVDA:** Tricuspid Valve (>50% of cases). * **Most common organism in IVDA IE:** *Staphylococcus aureus*. * **Clinical Sign:** A holosystolic murmur at the left lower sternal border that increases with inspiration (**Carvallo’s sign**) is characteristic of tricuspid regurgitation [1]. * **Radiology:** Look for "septic pulmonary emboli" (multiple wedge-shaped opacities) on a chest X-ray, which are common complications of right-sided IE.

Question 715: Asynchronous cardioversion is indicated in which of the following arrhythmias?

A. Atrial fibrillation
B. Ventricular fibrillation (Correct Answer)
C. Atrial flutter
D. Ventricular tachycardia

Explanation: ### Explanation **Core Concept: Synchronized vs. Asynchronous Cardioversion** The fundamental difference between synchronized cardioversion and asynchronous cardioversion (defibrillation) lies in the timing of the electrical shock. * **Synchronized cardioversion** delivers a shock timed with the **R-wave** of the QRS complex. This avoids the "vulnerable period" (the T-wave), preventing the induction of ventricular fibrillation (VF) [2]. * **Asynchronous cardioversion (Defibrillation)** delivers a high-energy shock immediately upon pressing the button, regardless of the cardiac cycle. This is used when there is no organized electrical activity (no R-wave) to track. **Why Ventricular Fibrillation (Option B) is Correct:** In VF, the ventricles exhibit chaotic, rapid electrical activity with no identifiable QRS complexes or T-waves [1]. Since the machine cannot "sense" an R-wave to synchronize with, an asynchronous shock is mandatory to depolarize the entire myocardium simultaneously, allowing the natural pacemaker to resume control [1], [3]. **Why Other Options are Incorrect:** * **Atrial Fibrillation (A) & Atrial Flutter (C):** These are supraventricular tachyarrhythmias with distinct QRS complexes [2]. Synchronized shocks are used to avoid hitting the T-wave, which could trigger VF (the R-on-T phenomenon) [2]. * **Ventricular Tachycardia (D):** If the patient is stable or has a pulse, **synchronized** cardioversion is used. Asynchronous shocks are only used in *pulseless* VT, where the rhythm is treated identically to VF [1]. **NEET-PG High-Yield Pearls:** * **Energy Levels:** For VF, the initial dose is **200J (Biphasic)** or **360J (Monophasic)**. For Atrial Flutter, lower energy (50-100J) often suffices. * **The "R-on-T" Phenomenon:** Delivering a shock during the relative refractory period (T-wave) can lead to VF [2]. Synchronization prevents this. * **Mnemonic:** "If they have a **P**ulse, you **P**ause (Synchronize). If they are **D**ead, you **D**efibrillate (Asynchronous)."

Question 716: N-terminal pro-brain natriuretic peptide (NT-proBNP) levels are elevated in which of the following conditions?

A. Atrial fibrillation
B. Left heart failure (Correct Answer)
C. Pulmonary thromboembolism
D. Myocardial infarction

Explanation: **Explanation:** **NT-proBNP** is a pro-hormone released primarily from the ventricular myocardium in response to **increased wall stress** (stretch) caused by pressure or volume overload [1]. 1. **Why Left Heart Failure is the Correct Answer:** In Left Heart Failure (LHF), the left ventricle experiences increased end-diastolic pressure and volume [1]. This mechanical stretch triggers the synthesis of proBNP, which is cleaved into active BNP and the inactive **NT-proBNP**. NT-proBNP is a useful biomarker in the investigation of patients with breathlessness and is elevated in heart failure [1]. 2. **Analysis of Other Options:** While NT-proBNP can be elevated in several cardiac conditions, the question asks for the primary clinical association. * **Atrial Fibrillation (A):** Can cause mild elevations due to atrial stretch [1], but it is not the primary diagnostic use. * **Pulmonary Thromboembolism (C):** Causes right ventricular strain, which can elevate NT-proBNP, but this is a secondary marker of severity rather than the primary diagnostic condition. * **Myocardial Infarction (D):** Levels may rise due to ischemia-induced wall stress [1], but NT-proBNP is not used for the diagnosis of MI (Troponins are the markers of choice). **High-Yield Clinical Pearls for NEET-PG:** * **Cut-off values:** To rule out acute heart failure, use a threshold of **<300 pg/mL**. * **Age-adjusted cut-offs for diagnosis:** <50 years (>450), 50–75 years (>900), and >75 years (>1800 pg/mL). * **The "Obesity Paradox":** NT-proBNP levels are falsely **lower** in obese patients. * **Renal Clearance:** NT-proBNP is cleared by the kidneys; therefore, levels are significantly **elevated in chronic kidney disease (CKD)** regardless of heart failure status.

Question 717: Pulsus paradoxus is a characteristic feature of which of the following conditions?

A. Constrictive pericarditis
B. Cardiac Tamponade (Correct Answer)
C. Hypertrophic obstructive cardiomyopathy
D. Restrictive cardiomyopathy

Explanation: **Explanation:** **Pulsus Paradoxus** is defined as an exaggerated fall in systolic blood pressure (>10 mmHg) during inspiration. Under normal physiological conditions, inspiration increases venous return to the right heart, causing the interventricular septum to bulge slightly into the left ventricle (LV). In **Cardiac Tamponade**, the heart is compressed by fluid within a non-compliant pericardial space [1]. This leads to **exaggerated ventricular interdependence**: as the right ventricle expands during inspiration, it significantly displaces the septum toward the LV, reducing LV filling and stroke volume, thus dropping the systemic blood pressure. **Analysis of Options:** * **Cardiac Tamponade (Correct):** The classic condition associated with pulsus paradoxus due to the limited total intrapericardial volume [1]. * **Constrictive Pericarditis:** While it involves a rigid pericardium, pulsus paradoxus is seen in only about **33%** of cases [2]. The hallmark here is more commonly **Kussmaul’s sign** (paradoxical rise in JVP on inspiration). * **HOCM:** Characterized by **Pulsus Bisferiens** (double-peaked pulse). * **Restrictive Cardiomyopathy:** Primarily affects ventricular compliance rather than pericardial space; pulsus paradoxus is typically absent. **High-Yield Clinical Pearls for NEET-PG:** 1. **Beck’s Triad (Tamponade):** Hypotension, JVP distension, and muffled heart sounds. 2. **Reverse Pulsus Paradoxus:** Seen in Hypertrophic Obstructive Cardiomyopathy (HOCM) and during positive pressure ventilation. 3. **Non-Cardiac Causes:** Severe Asthma and COPD are common non-cardiac triggers for pulsus paradoxus. 4. **Important Distinction:** Pulsus paradoxus is **absent** in tamponade if there is a co-existing ASD or Aortic Regurgitation.

Question 718: Thrombolytics can provide relative mortality reduction in the treatment of acute myocardial infarction if the patient presents within what timeframe?

A. 6 hours
B. 12 hours (Correct Answer)
C. 18 hours
D. 24 hours

Explanation: The primary goal of reperfusion therapy in ST-elevation myocardial infarction (STEMI) is to "salvage" the myocardium. The benefit of thrombolytic therapy is highly time-dependent, following the principle that **"Time is Muscle."** **Why 12 hours is correct:** Clinical trials (such as GISSI-1 and ISIS-2) have demonstrated that thrombolytic therapy significantly reduces mortality when administered within **12 hours** of the onset of chest pain [1]. The maximum benefit is seen within the "Golden Hour" (first 60 minutes), but a statistically significant reduction in mortality persists up to the 12-hour mark [1]. Beyond 12 hours, the risk of myocardial rupture and intracranial hemorrhage often outweighs the benefit of salvaging already infarcted, necrotic tissue. **Analysis of Incorrect Options:** * **6 hours (Option A):** While the benefit is much higher within 6 hours (approximately 30 lives saved per 1000 treated), it is not the *upper limit* for mortality reduction [2]. * **18 & 24 hours (Options C & D):** Beyond 12 hours, thrombolysis is generally **not recommended** unless there is evidence of ongoing ischemia (stuttering chest pain) affecting a large area of myocardium. In stable patients presenting after 12 hours, the risks of fibrinolysis typically exceed the benefits. **High-Yield Clinical Pearls for NEET-PG:** * **PCI vs. Thrombolysis:** Primary Percutaneous Coronary Intervention (PCI) is the preferred reperfusion strategy if it can be performed within **120 minutes** of first medical contact [1]. * **Door-to-Needle Time:** The target for administering thrombolytics is within **30 minutes** of hospital arrival. * **Absolute Contraindications:** Prior intracranial hemorrhage, known structural cerebrovascular lesion, ischemic stroke within 3 months, or active internal bleeding. * **Agent of Choice:** Tenecteplase is currently preferred due to its high fibrin specificity and ease of single-bolus administration [1].

Question 719: A 36-year-old female presents with recurrent chest pain and palpitations of varying duration and severity, with 6-7 ectopic beats per minute. These symptoms are not related to exertion. Her blood pressure is 86 mm Hg and pulse rate is 86/min. What is the ideal investigation?

A. Echocardiography
B. Electrophysiological studies (Correct Answer)
C. Thallium study
D. Technetium pyrophosphate scan

Explanation: **Explanation:** The clinical presentation of a young female with recurrent chest pain, palpitations, and significant hypotension (BP 86/min) suggests a symptomatic cardiac arrhythmia [1]. The presence of frequent ectopic beats (6-7 per minute) and symptoms occurring independent of exertion point toward a primary electrical conduction issue rather than obstructive coronary artery disease [2]. **Why Electrophysiological Studies (EPS) is correct:** EPS is the definitive investigation for patients with symptomatic palpitations and suspected arrhythmias, especially when associated with hemodynamic instability (hypotension). It allows for the precise mapping of the cardiac conduction system, identification of the origin of ectopic beats, and provocation of tachyarrhythmias. In this patient, EPS is indicated to evaluate the cause of the palpitations and hypotension to guide definitive therapy (like radiofrequency ablation). **Why other options are incorrect:** * **Echocardiography:** While useful to rule out structural heart disease (like Mitral Valve Prolapse), it cannot diagnose the specific electrical etiology of the palpitations or ectopics. * **Thallium Study:** This is a myocardial perfusion scan used to detect inducible ischemia in suspected Coronary Artery Disease (CAD). The patient’s symptoms are not related to exertion, making CAD less likely [2]. * **Technetium Pyrophosphate Scan:** This "hot spot" imaging is used to detect acute myocardial infarction (3-5 days post-event) or certain types of cardiac amyloidosis. It has no role in evaluating palpitations or ectopics. **Clinical Pearls for NEET-PG:** * **Gold Standard:** EPS is the gold standard for diagnosing and localizing accessory pathways (e.g., WPW syndrome) and supraventricular tachycardias (SVT). * **Hypotension + Palpitations:** Always consider this a "red flag" indicating that the arrhythmia is causing hemodynamic compromise, necessitating invasive evaluation [1]. * **Ectopics:** While >10/min or >6/min are often cited as thresholds for concern, the presence of symptoms (hypotension) is the more critical driver for investigation [1].

Question 720: A 70-year-old woman with known diabetes mellitus presents with dyspnea, nausea, and a feeling of impending doom. What does the ECG show?

A. Myocardial infarction (Correct Answer)
B. Unstable angina
C. Prinzmetal angina
D. Aortic dissection

Explanation: ***Myocardial infarction*** - The combination of **dyspnea**, **nausea**, and **feeling of impending doom** represents an **atypical presentation** of MI common in **diabetic** and **elderly women**, who may lack classic chest pain due to **diabetic neuropathy**. - The ECG would show **ST-elevation** or **new Q waves** indicating **myocardial necrosis**, distinguishing it from other acute coronary syndromes. *Unstable angina* - Characterized by **chest pain at rest** or with minimal exertion, but **no ST-elevation** or cardiac enzyme elevation on ECG. - The ECG typically shows **ST-depression** or **T-wave inversions**, not the ST-elevation pattern expected in this clinical scenario. *Prinzmetal angina* - Caused by **coronary artery vasospasm** leading to **transient ST-elevation** that resolves when spasm ends. - Unlike MI, there is **no permanent myocardial damage** and symptoms typically occur at **rest** or during **sleep**, not with the constellation of symptoms described. *Aortic dissection* - Presents with **sudden, tearing chest pain** radiating to the back, often with **pulse differentials** between arms. - ECG findings are **non-specific** and may show **left ventricular hypertrophy** or signs of **aortic regurgitation**, not the acute changes of myocardial infarction.

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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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