Cardiology Practice Questions

Q: Which of the following can detect the volume of infarcted area in acute myocardial infarction?

Thallium scan. The correct answer is **Thallium scan (Thallium-201)**. Thallium-201 is a potassium analogue that is actively taken up by viable myocardial cells via the Na+/K+ ATPase pump. In the setting of an acute myocardial infarction (AMI), necrotic or infarcted tissue lacks blood flow and viable cell membranes, resulting in a "cold spot" (perfusion defect) on the scan [1]. The size and intensity of this defect are directly proportional to the **volume of the infarcted area**, making it a highly sensitive tool for quantifying the extent of myocardial damage. **Why other options are incorrect:** * **Echocardiogram:** While excellent for detecting regional wall motion abnormalities (RWMA) and estimating the Ejection Fraction (EF), it cannot definitively distinguish between acutely infarcted, stunned, or hibernating myocardium [2]. * **Electrocardiogram (ECG):** An ECG identifies the location (e.g., anterior vs. inferior) and the age of the infarct (ST-elevation vs. Q-waves), but it is a poor indicator of the actual volumetric size of the necrosis [4], [5]. * **CPK-MB Levels:** These enzymes indicate the *presence* and *timing* of myocardial injury. While the peak level roughly correlates with infarct size, it is influenced by reperfusion (washout phenomenon) and is less precise for volume measurement than nuclear imaging. **High-Yield Clinical Pearls for NEET-PG:** * **Thallium-201 vs. Technetium-99m Sestamibi:** Thallium is better for viability (redistribution), while Sestamibi is preferred for anatomical imaging due to better energy resolution. * **"Hot Spot" Imaging:** While Thallium shows "cold spots," **Technetium-99m Pyrophosphate** binds to calcium in necrotic cells, creating a "hot spot" (specifically used for infarct aging) [1]. * **Gold Standard:** Cardiac MRI (Delayed Gadolinium Enhancement) is currently the gold standard for quantifying infarct size [3], but among the given options, Thallium scan is the classic choice.

Q: Which enzyme is most specific for myocardial infarction?

Creatine phosphokinase-MB (CPK-MB). The diagnosis of Myocardial Infarction (MI) relies on detecting biomarkers released from necrotic cardiac myocytes. Among the options provided, **Creatine phosphokinase-MB (CPK-MB)** is the most specific enzyme for cardiac tissue [2]. 1. **Why CPK-MB is correct:** Creatine kinase exists as three isoenzymes. While CPK-MM is found in skeletal muscle and CPK-BB in the brain, **CPK-MB** is primarily localized in the myocardium (comprising about 15-30% of total CK in the heart). It rises within 4–6 hours of an infarct, peaks at 24 hours, and returns to baseline within 48–72 hours. Its rapid clearance makes it the "gold standard" for detecting **re-infarction**. 2. **Why other options are incorrect:** * **CPK-MM (Option A):** This is the predominant isoenzyme in skeletal muscle. Elevations occur in trauma, intramuscular injections, or strenuous exercise, making it non-specific for the heart. * **CPK-BB (Option B):** Found mainly in the brain and gastrointestinal tract; it is rarely elevated in the blood and has no role in MI diagnosis. * **LDH (Option D):** Lactate dehydrogenase is found in many tissues (liver, RBCs, muscle). While LDH-1 was historically used for late diagnosis, it lacks specificity and has been replaced by more modern markers [2]. **High-Yield NEET-PG Pearls:** * **Most Specific Marker overall:** **Cardiac Troponins (I and T)** are more specific and sensitive than CPK-MB and are the current preferred diagnostic markers [1]. * **Earliest Marker:** **Myoglobin** rises first (within 1–2 hours) but lacks specificity. * **Marker for Re-infarction:** **CPK-MB** is the answer of choice because Troponins remain elevated for up to 7–14 days, masking a second event.

Q: Which of the following conditions is characterized by the absence of P waves on an electrocardiogram?

Atrial fibrillation. **Explanation:** The hallmark of **Atrial Fibrillation (AF)** is the replacement of organized atrial activity (P waves) with rapid, chaotic, and irregular **fibrillatory (f) waves**. This occurs due to multiple re-entrant wavelets firing simultaneously in the atria, most commonly originating from the pulmonary veins [1]. Because the AV node is bombarded by these irregular impulses, the ventricular response is "irregularly irregular," which is the classic diagnostic triad for AF on an ECG: absence of P waves, presence of f-waves, and irregular R-R intervals [1]. **Analysis of Incorrect Options:** * **Atrial Asystole:** This refers to the total absence of atrial electrical and mechanical activity (atrial standstill). While P waves are absent, there are also no fibrillatory waves, and the rhythm is usually a slow junctional or ventricular escape rhythm, unlike the rapid/irregular nature of AF [2]. * **Ventricular Fibrillation (VF):** This is a terminal rhythm characterized by a complete lack of identifiable P, QRS, or T waves. The ECG shows a chaotic, undulating baseline. It is a pulseless rhythm requiring immediate defibrillation. * **Ventricular Tachycardia (VT):** This is characterized by wide QRS complexes. While P waves are often "hidden" or dissociated (AV dissociation), they are technically present but obscured by the rapid ventricular rate. **High-Yield NEET-PG Pearls:** * **Most common cause of AF:** Long-standing Hypertension (globally) and Mitral Stenosis (in developing countries). * **ECG finding:** "Irregularly irregular" rhythm. * **Treatment of choice:** Hemodynamically unstable patients require **synchronized DC cardioversion**. Stable patients are managed with rate control (Beta-blockers/CCBs) and anticoagulation (based on CHADS₂-VASc score). * **Ashman Phenomenon:** A long R-R interval followed by a short R-R interval resulting in an aberrantly conducted wide QRS complex, often seen in AF.

Q: All of the following murmurs may be heard in patients with aortic regurgitation except?

Pansystolic murmur.. **Explanation:** In Aortic Regurgitation (AR), the primary hemodynamic abnormality is the backflow of blood from the aorta into the left ventricle (LV) during diastole. **1. Why Pansystolic Murmur is the Correct Answer:** A **pansystolic (holosystolic) murmur** is characteristic of regurgitation between chambers with a significant pressure gradient throughout the entire systole, such as **Mitral Regurgitation (MR)** [3], **Tricuspid Regurgitation (TR)**, or **Ventricular Septal Defect (VSD)**. In AR, the pathology occurs during diastole; therefore, a pansystolic murmur is not a feature of isolated aortic regurgitation. **2. Analysis of Other Options:** * **High-pitched decrescendo diastolic murmur (Option A):** This is the **classical murmur of AR** [1]. It is heard best at the left sternal border (3rd/4th intercostal space) with the patient leaning forward in expiration. It represents the high-pressure regurgitant flow from the aorta to the LV [2]. * **Soft, low-pitched mid-diastolic rumbling murmur (Option B):** This is known as the **Austin Flint murmur**. It occurs because the regurgitant jet from the aorta strikes the anterior leaflet of the mitral valve, causing it to partially close and creating "functional" mitral stenosis [1]. * **Mid-systolic ejection flow murmur (Option C):** In chronic AR, the LV stroke volume is significantly increased (due to the added regurgitant volume). This high-volume flow across the aortic valve during systole creates a functional flow murmur [1], even in the absence of true aortic stenosis. **Clinical Pearls for NEET-PG:** * **Duroziez’s sign:** Systolic and diastolic bruits heard over the femoral artery. * **De Musset’s sign:** Head nodding in sync with the heartbeat. * **Corrigan’s Pulse:** "Water-hammer" or collapsing pulse. * **Hill’s Sign:** Popliteal systolic BP > Brachial systolic BP by >20 mmHg (most sensitive clinical sign for severity).

Q: Which of the following statements is FALSE about Takotsubo Cardiomyopathy?

Echocardiographic findings never revert back to normal.. **Takotsubo Cardiomyopathy**, also known as "Broken Heart Syndrome" or "Stress-induced Cardiomyopathy," is a transient cardiac syndrome that mimics an acute coronary syndrome (ACS) [1]. **Why Option D is the Correct (False) Statement:** The hallmark of Takotsubo Cardiomyopathy is its **reversibility**. Unlike a typical myocardial infarction where necrosis leads to permanent scarring, the regional wall motion abnormalities (RWMA) in Takotsubo usually **resolve completely within 1–4 weeks**. Therefore, echocardiographic findings do revert to normal as the myocardium recovers from "stunning." **Analysis of Other Options:** * **Option A (True):** The pathophysiology is driven by a **massive surge in catecholamines** (epinephrine/norepinephrine) triggered by intense emotional or physical stress. This leads to microvascular dysfunction or direct myocyte toxicity [3]. * **Option B (True):** It involves transient **LV contractile dysfunction**, typically manifesting as "apical ballooning" where the apex is akinetic/hypokinetic while the base remains hypercontractile [2]. * **Option C (True):** Patients most commonly present with **acute retrosternal chest pain** and dyspnea, often accompanied by ST-segment elevation on ECG and elevated cardiac biomarkers, making it indistinguishable from an MI at presentation [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Most common in **post-menopausal women** following a stressful trigger. * **Echocardiography:** Classic finding is **Apical Ballooning** (resembling a Japanese octopus trap, or "Takotsubo"). * **Coronary Angiography:** Crucial for diagnosis; it typically shows **absence of obstructive coronary artery disease** or acute plaque rupture. * **Prognosis:** Generally excellent with supportive care, though complications like heart failure or arrhythmias can occur in the acute phase [1].

Q: Which test is not useful in a patient with a history of syncopal attack?

PET Scan. **Explanation:** The primary goal in evaluating syncope is to distinguish between cardiac, orthostatic, and neurally mediated causes [1]. **Why PET Scan is the Correct Answer:** A **PET (Positron Emission Tomography) scan** is a functional imaging modality used primarily for assessing myocardial viability, detecting malignancy, or evaluating brain metabolism in dementia/epilepsy. It has **no established role** in the routine diagnostic workup of syncope, as it does not provide information on cardiac rhythm, valvular function, or autonomic reflexes—the three pillars of syncope evaluation. **Why the other options are incorrect:** * **Tilt Table Testing (HUTT):** This is the gold standard for diagnosing **Vasovagal Syncope** (neurally mediated) and orthostatic hypotension [2]. It provokes a bradycardic or hypotensive response in susceptible individuals. * **Holter Monitoring:** This is essential for detecting **transient arrhythmias** (e.g., Sick Sinus Syndrome, AV blocks, or VT) that may not be captured on a standard 12-lead ECG [3]. * **Electrophysiological (EP) Testing:** This invasive procedure is indicated in patients with structural heart disease or unexplained syncope where an arrhythmic cause is highly suspected but unproven by non-invasive means. **Clinical Pearls for NEET-PG:** * **Most common cause of syncope:** Vasovagal (Neurocardiogenic). * **Most common cardiac cause:** Arrhythmias. * **Initial investigation of choice:** A detailed history, physical exam (including orthostatic vitals), and a **12-lead ECG** [3]. * **San Francisco Syncope Rule (CHESS):** High-risk criteria include **C**HF, **H**ematocrit <30%, **E**CG abnormalities, **S**hortness of breath, and **S**ystolic BP <90 mmHg.

Question 1

Antibiotic prophylaxis for infective endocarditis is indicated in which of the following conditions?

Accepted Answer

Coarctation of the aorta

Answer

Isolated secundum atrial septal defect (ASD)

Answer

Mitral valve prolapse without regurgitation

Answer

Prior coronary artery bypass graft

Question 2

Rescue PCI is indicated for which of the following conditions?

Accepted Answer

Persistent chest pain with ST elevation more than 90 minutes after thrombolysis

Answer

Persistent chest pain with ST elevation more than 60 minutes after thrombolysis

Answer

Persistent chest pain with ST elevation more than 30 minutes after thrombolysis

Answer

Persistent chest pain with ST elevation more than 120 minutes after thrombolysis

Question 3

Which of the following can detect the volume of infarcted area in acute myocardial infarction?

Accepted Answer

Thallium scan

Answer

Echocardiogram

Answer

Electrocardiogram

Answer

Levels of Creatine Phosphokinase-MB (CPK-MB)

Question 4

Which enzyme is most specific for myocardial infarction?

Accepted Answer

Creatine phosphokinase-MB (CPK-MB)

Answer

Creatine phosphokinase-MM (CPK-MM)

Answer

Creatine phosphokinase-BB (CPK-BB)

Answer

Lactate dehydrogenase (LDH)

Question 5

Which of the following conditions is characterized by the absence of P waves on an electrocardiogram?

Accepted Answer

Atrial fibrillation

Answer

Atrial asystole

Answer

Ventricular fibrillation

Answer

Ventricular tachycardia

Question 6

All of the following murmurs may be heard in patients with aortic regurgitation except?

Accepted Answer

Pansystolic murmur.

Answer

High-pitched decrescendo diastolic murmur.

Answer

Soft, low-pitched mid-diastolic rumbling murmur.

Answer

Mid-systolic ejection flow murmur.

Question 7

Which of the following is NOT a manifestation of acute aortic dissection?

Accepted Answer

Mitral regurgitation

Answer

Pericardial effusion

Answer

Aortic regurgitation

Answer

Acute myocardial infarction

Question 8

Which of the following statements is FALSE about Takotsubo Cardiomyopathy?

Accepted Answer

Echocardiographic findings never revert back to normal.

Answer

It is due to major catecholamine discharge.

Answer

It involves left ventricular contractile dysfunction.

Answer

It presents with acute chest pain.

Question 9

Which test is not useful in a patient with a history of syncopal attack?

Accepted Answer

PET Scan

Answer

Electrophysiological testing

Answer

Tilt table testing

Answer

Holter monitoring

Question 10

A 63-year-old man presents with a triad of angina, syncope, and congestive heart failure. Which of the following valvular heart lesions can be suspected?

Accepted Answer

Aortic stenosis

Answer

Mitral stenosis

Answer

Tricuspid regurgitation

Answer

Aortic regurgitation

Cardiology — MCQs

Cardiology — MCQs

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