Cardiology Practice Questions

Q: All of the following heart sounds occur shortly after S2, except?

Ejection click. **Explanation:** The cardiac cycle is divided into systole and diastole [2]. **S2 (Second Heart Sound)** marks the end of ventricular systole and the beginning of diastole [2]. Therefore, sounds occurring shortly after S2 are **diastolic sounds**, while sounds occurring shortly after S1 (and before S2) are **systolic sounds** [3]. **Why Ejection Click is the Correct Answer:** An **Ejection Click** occurs in early systole, shortly after the **S1** heart sound [1]. It is caused by the abrupt opening of the semilunar valves (Aortic or Pulmonary) or the sudden distension of the great vessels. Since it occurs during the ejection phase of systole, it cannot occur after S2 [1]. **Analysis of Incorrect Options (Diastolic Sounds):** * **Opening Snap:** Occurs in early diastole due to the forceful opening of a stenosed but mobile Mitral valve (Mitral Stenosis) [1]. It follows S2 after a short interval (S2-OS interval) [1]. * **Pericardial Knock:** A high-pitched sound heard in early diastole in patients with **Constrictive Pericarditis**. It occurs due to the sudden cessation of ventricular filling by a rigid pericardium. * **Tumor Plop:** A low-pitched sound heard in early-to-mid diastole, caused by an **Atrial Myxoma** "plopping" into the atrioventricular orifice. **High-Yield Clinical Pearls for NEET-PG:** 1. **S2-OS Interval:** The shorter the interval between S2 and the Opening Snap, the more severe the Mitral Stenosis [1]. 2. **S3 vs. Pericardial Knock:** Both occur in early diastole, but the Pericardial Knock occurs earlier and is higher pitched than a physiological or pathological S3. 3. **Non-Ejection Click:** Mid-systolic clicks are classically associated with **Mitral Valve Prolapse (MVP)** [1]. 4. **Ejection Click Exception:** An Aortic ejection click is typically heard best at the apex and does not vary with respiration, whereas a Pulmonary ejection click decreases in intensity during inspiration.

Q: Troponin-T is preferable to CPK-MB in the diagnosis of acute myocardial infarction in all of the following situations except?

Reinfarction after 4 days. **Explanation:** The diagnosis of Acute Myocardial Infarction (AMI) relies on the kinetics of cardiac biomarkers. The choice between Troponin-T (cTnT) and CK-MB depends on their respective "washout" periods and sensitivity. **1. Why "Reinfarction after 4 days" is the correct answer:** Troponin-T levels remain elevated in the blood for **10–14 days** after an initial MI. If a patient suffers a second infarct (reinfarction) on day 4, the Troponin levels will already be high from the first event, making it difficult to distinguish a new rise. In contrast, **CK-MB returns to baseline within 48–72 hours**. Therefore, if CK-MB rises again after day 3, it is a specific indicator of a new, acute reinfarction. **2. Analysis of Incorrect Options:** * **Bedside diagnosis (A):** Rapid bedside Troponin assays (Point-of-Care Testing) are highly sensitive and specific, making them superior to CK-MB for quick triage in the ER. * **After CABG (B):** Troponins are more cardio-specific [1]. While CK-MB can be elevated due to skeletal muscle trauma during surgery, Troponins provide a more accurate assessment of actual myocardial injury during the procedure [1]. * **Small Infarct (D):** Troponins are significantly more sensitive than CK-MB. They can detect "micro-infarctions" (e.g., in NSTEMI) that might not cause a rise in CK-MB levels. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Marker:** Myoglobin (rises in 1–2 hours), but it is non-specific [2]. * **Most Specific Marker:** Cardiac Troponin I (cTnI). * **Marker for Reinfarction:** CK-MB (due to short half-life). * **Troponin Kinetics:** Rises in 3–4 hours, peaks at 18–24 hours, stays elevated for 10–14 days. * **False Positive Troponin:** Can occur in Chronic Kidney Disease (CKD), Pulmonary Embolism, and Sepsis.

Q: What energy level is appropriate for defibrillation of ventricular fibrillation?

250 J. The management of Ventricular Fibrillation (VF) and pulseless Ventricular Tachycardia (pVT) relies on immediate high-energy unsynchronized shocks (defibrillation) [1]. **Why 250 J is the correct answer:** In the context of traditional **Monophasic Defibrillators**, the standard protocol follows a "step-up" approach if the initial shock fails. While the first shock is typically 200 J, the second shock is administered at **250 J** (or 300 J depending on the specific guideline version), and the third at 360 J. In many classic medical examinations like NEET-PG, 250 J is recognized as the appropriate intermediate energy level for escalating therapy in monophasic waveforms. **Analysis of Incorrect Options:** * **A. 120 J:** This is the starting dose for **Biphasic Defibrillators** (range 120–200 J). For monophasic devices, 120 J is insufficient for VF. * **C. 300 J:** While 300 J is used as the second or third shock in some monophasic protocols, 250 J is the more classically tested "next step" after an initial 200 J failure in older standardized curricula. * **D. 400 J:** This exceeds the standard maximum recommended energy level. The maximum dose for adult defibrillation is typically capped at **360 J** to prevent myocardial damage. **Clinical Pearls for NEET-PG:** * **Biphasic vs. Monophasic:** Biphasic is now the gold standard as it requires less energy (120–200 J) and causes less post-shock myocardial dysfunction. * **Synchronized vs. Unsynchronized:** Use **Unsynchronized** shocks (Defibrillation) for VF/Pulseless VT [1]. Use **Synchronized Cardioversion** for unstable SVT, Atrial Fibrillation, or VT with a pulse. * **Pediatric Dose:** Initial dose is **2 J/kg**, second dose is **4 J/kg**, and subsequent doses $\geq$ 4 J/kg (max 10 J/kg or adult dose).

Q: Renal artery stenosis may occur in all of the following conditions except?

Polyarteritis nodosa. **Explanation:** The correct answer is **Polyarteritis nodosa (PAN)**. The underlying medical concept involves the **size and location of the vessels** affected. Renal artery stenosis (RAS) involves the narrowing of the main renal artery or its primary branches. * **Why Polyarteritis nodosa is the exception:** PAN is a systemic necrotizing vasculitis that typically affects **medium and small-sized muscular arteries**. In the kidneys, it involves the **interlobar and arcuate arteries** (intra-renal vessels), rather than the main renal artery. Instead of stenosis, PAN is characterized by the formation of **microaneurysms** (appearing as a "string of pearls" on angiography), which can rupture or lead to infarction, but not classic renal artery stenosis. **Analysis of other options:** * **Atherosclerosis:** The most common cause of RAS (approx. 90%), typically involving the **proximal third/ostium** of the renal artery in elderly patients. * **Fibromuscular Dysplasia (FMD):** The second most common cause, typically seen in **young females**. It involves the **distal two-thirds** of the renal artery, showing a "string of beads" appearance. * **Takayasu’s Arteritis:** A large-vessel vasculitis ("pulseless disease") that commonly involves the aorta and its major branches, including the **ostium of the renal arteries**, leading to stenosis and renovascular hypertension. **High-Yield Clinical Pearls for NEET-PG:** 1. **Gold Standard Investigation:** Renal Angiography is the definitive test for diagnosing RAS. 2. **Clinical Clue:** Suspect RAS if a patient develops acute renal failure after starting **ACE inhibitors** (due to loss of efferent arteriolar vasoconstriction). 3. **Bruit:** A systolic-diastolic epigastric bruit is highly suggestive of RAS. 4. **PAN Association:** PAN is strongly associated with **Hepatitis B** (HBsAg positivity) and characteristically **spares the lungs**.

Q: Which of the following represents the earliest ECG changes in a patient with Hypokalemia?

Flattening of T wave. **Explanation:** In hypokalemia, the resting membrane potential of cardiac myocytes becomes more negative, leading to delayed repolarization. The ECG changes follow a progressive, sequential pattern as serum potassium levels drop [1]. **Why "Flattening of T wave" is correct:** The **earliest** recognizable ECG change in hypokalemia is the **decrease in T-wave amplitude (flattening)**. As potassium levels fall below 3.0 mEq/L, the T-wave becomes progressively lower in voltage. This occurs before the prominent appearance of U waves or ST-segment depression. **Analysis of Incorrect Options:** * **C. Development of U wave:** While highly characteristic of hypokalemia, prominent U waves typically appear *after* the T-wave has started to flatten. The U wave is best seen in precordial leads (V2-V4). * **D. Fusion of TU waves:** This occurs in more severe hypokalemia. As the T-wave flattens and the U-wave grows, they eventually merge, often leading to a "pseudo-prolonged QT interval" (actually a QU interval). * **A. Pseudo-P-Pulmonale:** This refers to an increase in P-wave amplitude and duration. While it can occur in hypokalemia, it is a later finding compared to T-wave changes [1]. **High-Yield NEET-PG Pearls:** * **Sequence of Changes:** T-wave flattening → ST depression → Prominent U waves → TU fusion (QU prolongation). * **The "QU" Interval:** In hypokalemia, the QT interval appears prolonged, but it is actually the **QU interval** due to T and U wave fusion. * **Arrhythmias:** Hypokalemia predisposes patients to Digoxin toxicity and can trigger *Torsades de Pointes* due to the prolonged repolarization phase [1]. * **Differential:** Remember that **Hyperkalemia** presents with the opposite early change: Tall, peaked "tented" T-waves [1].

Q: A 58-year-old man with no prior cardiac history presents with retrosternal chest pain starting at rest and lasting 30 minutes. The pain radiates to the left arm and is associated with diaphoresis and dyspnea. His blood pressure is 150/90 mm Hg, pulse 100/min, the heart sounds are normal, and the lungs are clear to auscultation. Which of the following is the next most appropriate investigation?

Electrocardiogram (ECG). ### Explanation **1. Why the Correct Answer (D) is Right:** The patient presents with classic symptoms of **Acute Coronary Syndrome (ACS)**: retrosternal chest pain at rest, radiation to the left arm, diaphoresis, and dyspnea [1], [5]. In any patient with suspected ACS, the **Electrocardiogram (ECG)** is the most critical initial investigation. According to AHA/ESC guidelines, an ECG should be performed and interpreted within **10 minutes** of presentation. It is the primary tool used to triage patients into ST-Elevation Myocardial Infarction (STEMI) or Non-ST Elevation ACS (NSTE-ACS), which dictates immediate management (e.g., urgent reperfusion vs. stabilization) [2], [4]. **2. Why the Other Options are Wrong:** * **Cardiac Troponin (C):** While essential for diagnosing NSTEMI, troponins take 3–6 hours to rise significantly [3]. Waiting for lab results delays the diagnosis of a STEMI, which can be identified immediately on an ECG. * **Chest X-ray (B):** CXR is useful to rule out differential diagnoses like pneumonia or pneumothorax, but it is not the priority when an MI is suspected. It should be performed after the ECG. * **CT Scan - Chest (A):** This is indicated if aortic dissection or pulmonary embolism is strongly suspected. However, given the classic presentation of ACS, an ECG must always come first to rule out cardiac ischemia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Door-to-ECG time:** Goal is <10 minutes. * **Gold Standard for STEMI:** Primary Percutaneous Coronary Intervention (PCI) within 90 minutes of medical contact. * **Silent MI:** Common in elderly, females, and diabetics; often presents with "anginal equivalents" like dyspnea or epigastric pain [5]. * **ECG Evolution:** Hyperacute T-waves → ST elevation → Q waves → T-wave inversion [4].

Q: Which valve is most commonly affected in Rheumatic Heart Disease?

Mitral. In Rheumatic Heart Disease (RHD), the **Mitral valve** is the most frequently affected valve (involved in approximately 95% of cases) [1]. The underlying mechanism involves molecular mimicry, where antibodies against Group A Streptococcal M-protein cross-react with endocardial structures. The mitral valve is most susceptible due to the high hemodynamic stress and pressure gradients it handles during ventricular systole, leading to valvulitis, chordae thickening, and eventually, the classic "fish-mouth" or "button-hole" stenosis. All patients with mitral stenosis, particularly those with atrial fibrillation, are at risk from left atrial thrombosis and systemic thromboembolism [1]. **2. Analysis of Incorrect Options:** * **Aortic Valve (Option C):** This is the **second most common** valve involved. It is rarely affected in isolation and is usually seen in combination with mitral valve disease. Isolated aortic involvement is more common in males. * **Tricuspid Valve (Option B):** This is the **third most common** valve affected. It is almost never involved alone and typically presents as tricuspid regurgitation secondary to mitral valve pathology and pulmonary hypertension [1]. * **Pulmonary Valve (Option D):** This is the **least commonly** affected valve in RHD. Involvement is extremely rare and usually clinically insignificant. **3. NEET-PG High-Yield Pearls:** * **Order of Frequency:** Mitral > Aortic > Tricuspid > Pulmonary (**M > A > T > P**). * **Most Common Lesion:** Mitral Regurgitation (MR) is the most common early finding in acute rheumatic carditis, while Mitral Stenosis (MS) is the hallmark of chronic RHD [1]. * **Pathognomonic Feature:** **Aschoff bodies** (granulomatous lesions) in the myocardium are diagnostic of acute rheumatic fever. * **McCallum’s Patch:** A corrugated area of endocardial thickening usually found in the posterior wall of the left atrium, caused by regurgitant jets in MR.

Question 1

Which organism most commonly leads to infective endocarditis?

Accepted Answer

Staphylococcus aureus

Answer

Klebsiella

Answer

Streptococcus pneumoniae

Answer

Neisseria meningitidis

Question 2

All of the following heart sounds occur shortly after S2, except?

Accepted Answer

Ejection click

Answer

Opening snap

Answer

Pericardial knock

Answer

Tumor plop

Question 3

All of the following may be seen in a patient with cardiac tamponade, except?

Accepted Answer

Atrial flutter

Answer

Raised JVP

Answer

Hypotension with narrowed pulse pressure

Answer

Muffled heart sounds

Question 4

Troponin-T is preferable to CPK-MB in the diagnosis of acute myocardial infarction in all of the following situations except?

Accepted Answer

Reinfarction after 4 days

Answer

Bedside diagnosis of myocardial infarction

Answer

After coronary artery bypass grafting

Answer

Small infarct

Question 5

A 65-year-old man with a long history of hypertension presents to the emergency department with tearing chest pain that radiates to the back. An electrocardiogram is normal, as are cardiac enzymes. A chest radiograph demonstrates widening of the mediastinum. What is the most likely diagnosis?

Accepted Answer

Dissecting aneurysm

Answer

Arteriovenous fistula

Answer

Atherosclerotic aneurysm

Answer

Syphilitic aneurysm

Question 6

What energy level is appropriate for defibrillation of ventricular fibrillation?

Accepted Answer

250 J

Answer

120 J

Answer

300 J

Answer

400 J

Question 7

Renal artery stenosis may occur in all of the following conditions except?

Accepted Answer

Polyarteritis nodosa

Answer

Atherosclerosis

Answer

Fibromuscular dysplasia

Answer

Takayasu's arteritis

Question 8

Which of the following represents the earliest ECG changes in a patient with Hypokalemia?

Accepted Answer

Flattening of T wave

Answer

Pseudo-P-Pulmonale

Answer

Development of U wave

Answer

Fusion of TU waves

Question 9

A 58-year-old man with no prior cardiac history presents with retrosternal chest pain starting at rest and lasting 30 minutes. The pain radiates to the left arm and is associated with diaphoresis and dyspnea. His blood pressure is 150/90 mm Hg, pulse 100/min, the heart sounds are normal, and the lungs are clear to auscultation. Which of the following is the next most appropriate investigation?

Accepted Answer

Electrocardiogram (ECG)

Answer

CT scan - chest

Answer

Chest X-ray (CXR)

Answer

Cardiac troponin

Question 10

Which valve is most commonly affected in Rheumatic Heart Disease?

Accepted Answer

Mitral

Answer

Tricuspid

Answer

Aortic

Answer

Pulmonary

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