Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 1381: An elderly man with a prosthetic heart valve presents with fever and a new heart murmur. Blood cultures grow gram-positive cocci in chains. What is the recommended management for this patient regarding valve replacement and antibiotic therapy?

A. Antibiotic therapy alone with penicillin. (Correct Answer)
B. Valve monitoring with ceftriaxone.
C. Anticoagulation therapy with heparin.
D. Immediate valve replacement and vancomycin therapy.

Explanation: The likely diagnosis is infective endocarditis caused by **Streptococcus viridans**, a common pathogen for **subacute endocarditis** on prosthetic valves [1]. Initial management typically involves empirical antibiotic therapy, and given the gram-positive cocci in chains and the clinical context, **high-dose penicillin** is often the preferred initial treatment for susceptible organisms [2]. While **ceftriaxone** is a broad-spectrum antibiotic, it is not the primary choice for suspected **Streptococcus viridans** endocarditis if penicillin-sensitive. **Valve monitoring alone** is insufficient, as active infection requires aggressive antibiotic treatment to prevent complications. **Anticoagulation** is not a primary treatment for infective endocarditis and can increase the risk of **hemorrhagic complications**, especially if there are vegetations or systemic embolization [3]. It does not address the underlying bacterial infection. **Immediate valve replacement** is generally reserved for cases with severe valvular dysfunction, large vegetations, recurrent emboli, or persistent infection despite adequate antibiotics [3]. While **vancomycin** is appropriate for methicillin-resistant bacteria, **penicillin** is preferred for penicillin-susceptible streptococci due to its efficacy and lower toxicity profile.

Question 1382: A 72-year-old man presents with progressive dyspnea on exertion and a history of ischemic heart disease. An echocardiogram shows diastolic dysfunction. What is the most likely diagnosis?

A. Acute myocardial infarction
B. Chronic heart failure (Correct Answer)
C. Pulmonary embolism
D. Valvular heart disease

Explanation: ***Chronic heart failure*** - Progressive **dyspnea on exertion** in an elderly patient with **ischemic heart disease** and **diastolic dysfunction** on echocardiogram are all classic features [1]. - **Diastolic dysfunction** is a hallmark of **heart failure with preserved ejection fraction (HFpEF),** a common form of chronic heart failure [1]. *Acute myocardial infarction* - Typically presents with **acute chest pain** and sudden onset of symptoms, rather than progressive dyspnea [2]. - Echocardiogram findings would usually show new regional wall motion abnormalities, which are not mentioned here. *Pulmonary embolism* - Often causes **acute-onset dyspnea** and pleuritic chest pain, potentially with hypoxia and hemodynamic instability. - While it can cause right heart strain, it wouldn't typically manifest primarily as isolated **diastolic dysfunction** *Valvular heart disease* - Although it can cause dyspnea and heart failure, the echocardiogram description only mentions **diastolic dysfunction**, not specific valvular abnormalities such as stenosis or regurgitation. - The history of ischemic heart disease points more strongly towards myocardial rather than primary valvular pathology.

Question 1383: In patients with suspected acute coronary syndrome, which biomarker is the most reliable for early diagnosis?

A. C-reactive protein
B. Serum cholesterol
C. Troponin (Correct Answer)
D. Myoglobin

Explanation: ***Troponin*** - **Cardiac troponins (cTnI and cTnT)** are highly specific and sensitive biomarkers for myocardial injury, released into the bloodstream within 2-4 hours of damage [1], [2]. - Their prolonged elevation, typically lasting several days, makes them the **most reliable marker** for diagnosing acute coronary syndrome (ACS) [1], [3]. *C-reactive protein* - **C-reactive protein (CRP)** is an acute-phase reactant indicative of systemic inflammation, which can be elevated in many conditions, not just ACS. - While elevated CRP levels are associated with increased risk of cardiovascular events, it is **not specific enough** for the early diagnosis of acute myocardial injury. *Serum cholesterol* - **Serum cholesterol** levels reflect long-term cardiovascular risk and are critically important in the prevention and management of atherosclerosis. - They do not change rapidly enough during an acute event to be useful in the **early diagnosis of ACS**. *Myoglobin* - **Myoglobin** is an early marker of muscle damage, including cardiac muscle, and can rise within 1-2 hours of myocardial infarction. - However, its **lack of cardiac specificity** (also present in skeletal muscle) and rapid clearance from the bloodstream limit its diagnostic utility compared to troponin.

Question 1384: A 45-year-old male presents with acute shortness of breath and chest pain. An ECG reveals ST elevation in leads V1 to V4. Which coronary artery is most likely occluded?

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

Explanation: *Left anterior descending artery* - **ST elevation** in leads **V1 to V4** indicates an **anterior myocardial infarction** [1]. - The **left anterior descending (LAD) artery** supplies the **anterior wall of the left ventricle** and the anterior two-thirds of the septum [2]. *Right coronary artery* - Occlusion of the **right coronary artery (RCA)** typically causes **inferior myocardial infarctions**, reflected by ST elevation in leads **II, III, and aVF**. - It often supplies the **right ventricle**, inferior wall of the left ventricle, and the atrioventricular (AV) node. *Left circumflex artery* - Occlusion of the **left circumflex artery (LCX)** usually leads to **lateral or posterior myocardial infarctions**, with ST elevation in leads **I, aVL, V5, V6** or **ST depression in V1-V3** (posterior MI). - It supplies the **lateral and posterior walls of the left ventricle**. *Posterior descending artery* - The **posterior descending artery (PDA)** is typically a branch of the RCA (in 85% of individuals) and supplies the **inferior-posterior wall of the left ventricle** and the posterior third of the interventricular septum. - Occlusion of the PDA, whether from the RCA or LCX, would primarily cause an **inferior or inferoposterior MI**, not anterior, with ECG changes in leads **II, III, aVF**, and potentially **V7-V9**.

Question 1385: A 45-year-old male with hypertension presents with palpitations and occasional dizziness. An ECG reveals intermittent atrial fibrillation. What is the most appropriate first-line treatment?

A. Immediate cardioversion
B. Rate control with beta-blockers (Correct Answer)
C. Rhythm control with amiodarone
D. Implantation of a pacemaker

Explanation: Rate control with beta-blockers - **Beta-blockers** are considered first-line for rate control in patients with **atrial fibrillation** and rapid ventricular response, especially in the absence of acute hemodynamic instability [1]. - They reduce the heart rate by blocking beta-adrenergic receptors, thereby improving symptoms like palpitations and dizziness [2]. Immediate cardioversion - **Immediate cardioversion** is typically reserved for patients with **hemodynamically unstable atrial fibrillation**, presenting with symptoms such as severe hypotension, acute heart failure, or ongoing myocardial ischemia. - The patient's symptoms of occasional dizziness and palpitations without further details of instability do not warrant immediate cardioversion. Rhythm control with amiodarone - **Rhythm control strategies** like amiodarone are primarily considered when **rate control** is insufficient or when symptoms persist despite adequate rate control, aiming to restore and maintain normal sinus rhythm [1]. - Amiodarone has significant side effects and is generally not the first-line treatment for uncomplicated intermittent atrial fibrillation. Implantation of a pacemaker - **Pacemaker implantation** is indicated for symptomatic **bradyarrhythmias**, such as sick sinus syndrome or complete heart block, to maintain an adequate heart rate [3]. - This patient presents with an arrhythmia characterized by a rapid and irregular heart rate (**atrial fibrillation**), not a slow heart rate requiring pacing.

Question 1386: A patient with a history of coronary artery disease and hypertension is in the postoperative period after major surgery. He suddenly develops chest pain and dyspnea. Analyze the situation and determine the most appropriate initial investigation.

A. Obtain a chest X-ray
B. Perform a 12-lead ECG (Correct Answer)
C. Order cardiac enzymes
D. Initiate anticoagulation therapy

Explanation: ***Perform a 12-lead ECG*** - A 12-lead ECG is crucial for rapidly assessing **cardiac ischemia or infarction**, which is a high risk in a patient with a history of **coronary artery disease** presenting with chest pain and dyspnea post-surgery [1]. - It can identify **ST-segment elevation or depression**, T-wave inversions, or new Q waves, guiding immediate management to prevent further myocardial damage [2]. *Obtain a chest X-ray* - While a chest X-ray can detect **pulmonary pathology** like pneumothorax, effusion, or pneumonia, it is less immediate in diagnosing acute cardiac events in this context. - It would be a secondary investigation if the ECG does not reveal an acute cardiac cause, or if **pulmonary embolism** or **pneumonia** remains a strong suspicion. *Order cardiac enzymes* - Cardiac enzymes (e.g., **troponin**) are important for confirming myocardial injury but their levels rise hours after the event, making them less useful for **immediate diagnosis** and guiding initial, time-sensitive interventions [1]. - An ECG provides **real-time information** on electrical activity, which is critical for making urgent clinical decisions regarding ischemia or infarction. *Initiate anticoagulation therapy* - Initiating anticoagulation without a definitive diagnosis could be harmful, especially in a **postoperative patient** with potential **bleeding risks**. - While conditions like pulmonary embolism or DVT might warrant anticoagulation, an immediate ECG is needed to rule out or confirm life-threatening cardiac ischemia first.

Question 1387: Which of the following risk factors is most strongly associated with the development of embolic stroke in atrial fibrillation?

A. Hypertension
B. Diabetes mellitus
C. Previous stroke (Correct Answer)
D. Coronary artery disease

Explanation: ***Previous stroke*** - A history of **prior ischemic stroke or transient ischemic attack (TIA)** is the strongest independent predictor of future embolic stroke in patients with **atrial fibrillation (AF)**. - This risk factor is weighted heavily in stroke risk stratification scores like **CHA2DS2-VASc** (2 points for previous stroke/TIA). *Hypertension* - **Hypertension** is a significant risk factor for stroke in general and contributes to cardiovascular morbidity. - However, its association with *embolic stroke specifically in the context of AF* is less potent compared to a **prior stroke**. *Diabetes mellitus* - **Diabetes mellitus** increases the overall risk of stroke and is an important cardiovascular risk factor. - While it contributes to the risk of stroke in AF, its predictive power for *embolic stroke* is secondary to a **previous thrombotic event**. *Coronary artery disease* - **Coronary artery disease (CAD)** often coexists with AF and shares common risk factors, contributing to overall cardiovascular risk. - While CAD indicates systemic vascular disease, it is **not as direct a predictor** of *embolic stroke from AF* as a previous embolic event.

Question 1388: A 65-year-old man presents with palpitations and is found to have atrial fibrillation. What is the primary goal of therapy for this patient?

A. Rate control
B. Rhythm control
C. Anticoagulation (Correct Answer)
D. Cardioversion

Explanation: ***Anticoagulation*** - The primary goal in a patient with new-onset atrial fibrillation is to prevent **thromboembolic events**, particularly **stroke**, which can be devastating. [1] - While rate and rhythm control are important, addressing the **risk of clot formation** in the atria due to the irregular rhythm is the most immediate and critical priority for patient safety. [1] *Rate control* - This strategy aims to **slow the ventricular response** to atrial fibrillation to a more physiological rate, typically reducing symptoms like palpitations and improving cardiac output. [1] - While important for symptom management and preventing **tachycardia-induced cardiomyopathy**, it does not directly address the increased risk of stroke. [1] *Rhythm control* - This approach aims to restore and maintain **normal sinus rhythm**, which can alleviate symptoms and potentially improve cardiac function. [1] - While desirable, rhythm control carries its own risks (e.g., from antiarrhythmic drugs or procedures) and has not consistently shown superior outcomes over rate control in preventing stroke when adequate anticoagulation is used. *Cardioversion* - This procedure uses an electrical shock or medication to **convert atrial fibrillation back to normal sinus rhythm**. - While sometimes necessary, particularly in hemodynamically unstable patients, it is often performed after a period of anticoagulation to reduce the risk of thromboembolic events associated with the conversion process itself.

Question 1389: A patient presents with acute myocardial infarction and a history of severe chest pain. Which anatomical area of the heart is most commonly affected in such cases?

A. Left ventricle (Correct Answer)
B. Right ventricle
C. Left atrium
D. Right atrium

Explanation: Left ventricle - The **left ventricle** has the largest muscle mass and performs the most work, making it particularly vulnerable to **ischemic injury** during myocardial infarction. - Due to the high **oxygen demand** and pressure workload, the left ventricle is the most common site of **myocardial infarction** [2]. *Right ventricle* - While the right ventricle can be affected, **right ventricular infarction** is less common and typically occurs secondary to **inferior wall myocardial infarction** affecting the left ventricle [1]. - Symptoms usually include **hypotension** and **jugular venous distention**, which are not universally present in all acute MIs. *Left atrium* - The **left atrium** primarily serves as a reservoir for blood and has a relatively small muscle mass, making isolated **left atrial infarction** extremely rare. - Infarction of the left atrium is usually asymptomatic and clinically insignificant compared to ventricular involvement. *Right atrium* - Similar to the left atrium, the **right atrium** has a small muscle mass and a lower metabolic demand, making it an uncommon site for infarction. - Isolated **right atrial infarction** is exceptionally rare and often found incidentally during autopsy in extensive myocardial infarctions.

Question 1390: What is the clinical significance of elevated levels of homocysteine?

A. It is a risk factor for cardiovascular diseases (Correct Answer)
B. It indicates high levels of vitamin B12
C. It is associated with decreased risk of diabetes
D. It suggests enhanced lipid metabolism

Explanation: ***It is a risk factor for cardiovascular diseases*** - Elevated **homocysteine** levels are associated with increased risk of **atherosclerosis**, **coronary artery disease**, **stroke**, and **peripheral vascular disease**. - High levels may promote **endothelial dysfunction**, oxidative stress, and inflammation, contributing to cardiovascular pathology. *It indicates high levels of vitamin B12* - **High homocysteine** levels are typically indicative of **deficiencies in vitamin B12**, folate, or vitamin B6, which are crucial for its metabolism [1]. - Therefore, an inverse relationship exists; deficiency, not high levels, of B12 results in elevated homocysteine [1]. *It is associated with decreased risk of diabetes* - There is no evidence suggesting elevated homocysteine is associated with a decreased risk of **diabetes**. - In fact, some studies show a positive correlation between **hyperhomocysteinemia** and an increased risk of developing **type 2 diabetes**. *It suggests enhanced lipid metabolism* - Elevated **homocysteine** levels are associated with impaired, rather than enhanced, **lipid metabolism** and are often linked with **dyslipidemia**. - Poor lipid metabolism can worsen the **atherogenic effects** of high homocysteine.

Practice by Chapter

Coronary Artery Disease and Angina

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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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Non-invasive Cardiac Diagnostics

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Preventive Cardiology

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Cardiology — MCQs

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