Cardiology Practice Questions

Q: Which of the following conditions presents with a constant PR interval?

Second-degree atrioventricular block, Mobitz type II. In atrioventricular (AV) blocks, the behavior of the PR interval is the primary diagnostic feature used to differentiate the types. ### **Why Mobitz Type II is the Correct Answer** In **Mobitz Type II second-degree AV block**, the conduction system (usually below the AV node, in the His-Purkinje system) fails suddenly and unpredictably. Because the underlying conduction through the AV node is normal until the moment of the "drop," the **PR interval remains constant and fixed** for all conducted beats [1]. There is no progressive lengthening; a P-wave is simply followed by a sudden QRS drop [1]. ### **Analysis of Incorrect Options** * **First-degree AV block:** While the PR interval is constant, it is **prolonged** (>0.20 seconds) [1]. Every P-wave is followed by a QRS complex. * **Mobitz Type I (Wenckebach):** This is characterized by **progressive PR interval prolongation** until a QRS complex is dropped [1]. The PR interval is never constant. * **Third-degree (Complete) AV block:** There is total AV dissociation. P-waves and QRS complexes occur independently; therefore, the PR interval is **variable and inconsistent**. ### **High-Yield Clinical Pearls for NEET-PG** * **Site of Block:** Mobitz I usually occurs at the **AV node** (reversible/benign), while Mobitz II occurs **infra-nodal** (Bundle of His/Purkinje fibers) and is more dangerous [1]. * **Prognosis:** Mobitz II has a high risk of progressing to complete heart block and sudden cardiac death; it almost always requires a **permanent pacemaker**. * **Vagal Maneuvers:** Carotid sinus massage worsens Mobitz I but may paradoxically improve Mobitz II. Atropine improves Mobitz I but worsens Mobitz II.

Q: Which of the following is the best predictor of cardiovascular risk?

C-reactive protein (CRP). **Explanation:** **C-reactive protein (CRP)**, specifically measured via high-sensitivity assays (**hs-CRP**), is considered the best predictor of cardiovascular risk among the given options. Atherosclerosis is now recognized as a chronic inflammatory process rather than just lipid accumulation. hs-CRP is an acute-phase reactant produced by the liver in response to IL-6; it serves as a stable systemic marker of low-grade vascular inflammation. According to the AHA/CDC guidelines, hs-CRP levels >3 mg/L indicate high cardiovascular risk, even in individuals with normal LDL levels. **Analysis of Incorrect Options:** * **Antichlamydial antibody (Option A):** While *Chlamydia pneumoniae* has been associated with atherosclerotic plaques, clinical trials have failed to prove a consistent predictive value or therapeutic benefit from targeting the infection. * **Lipoprotein (a) (Option B):** Lp(a) is an independent genetic risk factor for CAD and stroke. However, it is not as strong a population-wide predictor as hs-CRP because its levels are largely genetically determined and do not reflect the dynamic inflammatory state of the vessels. * **Homocysteine (Option D):** Hyperhomocysteinemia is associated with endothelial damage. While it is a risk factor, lowering homocysteine levels (via B-vitamins) has not consistently shown a reduction in CV events, making it a weaker predictor than hs-CRP. **High-Yield Clinical Pearls for NEET-PG:** * **hs-CRP Risk Stratification:** 3 mg/L (High risk). * **Apolipoprotein B (ApoB):** Often cited as a better predictor than LDL-C because it measures the total number of atherogenic particles. * **Non-HDL Cholesterol:** Calculated as (Total Cholesterol – HDL); it is a superior predictor compared to LDL-C alone in patients with hypertriglyceridemia.

Q: Which of the following statements regarding cardiac tamponade is true?

Enlargement of the cardiac silhouette is present. **Explanation:** Cardiac tamponade occurs when fluid accumulation in the pericardial space increases intrapericardial pressure, leading to impaired diastolic filling and reduced cardiac output [1]. **Why Option B is Correct:** In cardiac tamponade, the pericardial sac expands to accommodate the fluid. On a chest X-ray, this manifests as an **enlargement of the cardiac silhouette**, often described as a **"Water-bottle heart"** or "Money-bag" appearance [1]. This is a classic radiological finding, though it requires at least 200ml of fluid to be visible. **Analysis of Incorrect Options:** * **A. Kussmaul sign:** This is a paradoxical rise in JVP during inspiration. It is a hallmark of **Constrictive Pericarditis**, not tamponade [2]. In tamponade, the rigid pericardium is absent, allowing the negative intrathoracic pressure to still be transmitted to the heart. * **C. Prominent y descent:** In tamponade, the high intrapericardial pressure prevents rapid ventricular filling during early diastole. Therefore, the **y descent is characteristically absent or blunted**. A prominent y descent is seen in Constrictive Pericarditis (Friedreich’s sign) [2]. * **D. Electrical alternans:** While this is a specific sign of tamponade (caused by the heart swinging in fluid), it is **not always present** [1]. It is a late finding and less common than silhouette enlargement. (Note: In some exam contexts, this is a "distractor" because while true, B is the more fundamental physiological/radiological expectation). **NEET-PG High-Yield Pearls:** * **Beck’s Triad:** Hypotension, JVP distension, and muffled heart sounds. * **Pulsus Paradoxus:** A drop in systolic BP >10 mmHg during inspiration (most sensitive physical sign). * **ECG:** Low voltage complexes and electrical alternans [1]. * **Treatment:** Immediate ultrasound-guided pericardiocentesis [1].

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

Ejection click. ### Explanation The cardiac cycle is divided into systole and diastole. **S2 (Second Heart Sound)** marks the end of ventricular systole and the beginning of diastole [2]. Therefore, sounds occurring "shortly after S2" are **early diastolic sounds**. **Why Ejection Click is the Correct Answer:** An **Ejection Click** is a high-pitched **systolic** sound [1]. It occurs shortly after **S1** (not S2), during the early phase of ventricular ejection. It is caused by the abrupt opening of semilunar valves (Aortic or Pulmonary) or the sudden distension of the great vessels [1]. Since it occurs during systole, it cannot occur after S2. **Analysis of Other Options (Diastolic Sounds):** * **Opening Snap:** Occurs in early diastole due to the forceful opening of a stenotic 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 sound heard in early-to-mid diastole as an **Atrial Myxoma** (usually left atrial) drops into the mitral orifice during ventricular filling. **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. **Ejection Click vs. Non-Ejection Click:** Ejection clicks (Aortic/Pulmonary stenosis) occur early in systole; Non-ejection clicks (Mitral Valve Prolapse) occur in mid-to-late systole [1]. 3. **High-Yield Sequence:** The chronological order of diastolic sounds after S2 is: **Opening Snap → Pericardial Knock → S3 → Tumor Plop → S4.**

Q: Which of the following is not a clinical sign associated with mitral stenosis?

Pan-systolic murmur which radiates to axilla. **Explanation:** The correct answer is **C. Pan-systolic murmur which radiates to axilla**. This murmur is the hallmark of **Mitral Regurgitation (MR)**, not Mitral Stenosis (MS) [2]. In MR, blood flows back from the high-pressure left ventricle into the low-pressure left atrium during systole, creating a high-pitched blowing murmur [2]. **Analysis of Options:** * **Malar Flush (Option A):** This is a classic sign of severe MS. It presents as plum-colored patches over the cheeks due to low cardiac output and systemic vasoconstriction leading to facial capillary congestion [1]. * **Atrial Fibrillation (Option B):** MS causes significant left atrial (LA) enlargement and pressure overload. This stretches the atrial fibers, leading to electrical remodeling and a very high incidence of AFib [1]. * **Tapping, Undisplaced Apex Beat (Option D):** In MS, the apex beat is "tapping" in character, which is actually a palpable loud first heart sound (S1) [1]. It remains **undisplaced** because MS is a pressure-loading lesion for the LA; the left ventricle remains normal-sized or even small. A displaced apex indicates ventricular enlargement (e.g., MR or AR). **NEET-PG High-Yield Pearls for Mitral Stenosis:** * **Auscultation:** Characterized by a loud S1, an **Opening Snap (OS)**, and a **mid-diastolic rumbling murmur** heard best at the apex in the left lateral position [1], [3]. * **Severity Marker:** The shorter the **A2-OS interval**, the more severe the stenosis (reflecting higher LA pressure) [3]. * **Graham Steell Murmur:** An early diastolic decrescendo murmur of pulmonary regurgitation seen in MS patients with secondary pulmonary hypertension [1]. * **Most common cause:** Rheumatic Heart Disease.

Q: What is diagnostic of a fresh myocardial infarction on ECG?

ST segment elevation. **Explanation:** The hallmark of an acute (fresh) transmural myocardial infarction is **ST-segment elevation** [2]. This occurs due to a "current of injury" resulting from severe, total occlusion of a coronary artery [2]. When the myocardium becomes acutely ischemic and damaged, it remains partially depolarized, creating a voltage gradient between the injured and healthy tissue, which manifests on the ECG as an elevation of the ST segment above the isoelectric line [2]. **Analysis of Options:** * **ST-segment elevation (Correct):** Diagnostic of an acute STEMI (ST-Elevation Myocardial Infarction) [1]. It indicates transmural injury and is the primary trigger for immediate reperfusion therapy (thrombolysis or PCI). * **QT interval prolongation:** This represents delayed ventricular repolarization. While it can be seen in electrolyte imbalances (hypocalcemia) or drug toxicities, it is not diagnostic of an acute MI. * **P mitrale:** This refers to a broad, notched P-wave in Lead II, signifying left atrial enlargement, typically seen in mitral stenosis, not acute ischemia. * **ST-segment depression:** This usually indicates subendocardial ischemia, NSTEMI, or reciprocal changes [1]. While significant, it is not the classic "diagnostic" sign of a fresh transmural infarction. **High-Yield Clinical Pearls for NEET-PG:** * **Evolution of ECG in MI:** Hyperacute T-waves (earliest sign) → ST-elevation → Q-waves (indicates necrosis) → T-wave inversion [1]. * **Pathological Q-waves:** Defined as >0.04s wide or >25% of the R-wave height; they signify a completed or old infarction [1]. * **Reciprocal Changes:** ST-depression in leads opposite to the site of infarction (e.g., ST-depression in II, III, aVF during a lateral wall MI) [1].

Q: Which of the following disorders is LEAST likely to cause high output failure?

Addison disease. **Explanation:** High-output heart failure (HOHF) occurs when the heart's cardiac output is elevated but still fails to meet the metabolic demands of the body, or can only do so at the expense of elevated filling pressures. This is typically driven by a decrease in **Systemic Vascular Resistance (SVR)** or an increase in metabolic rate. **Why Addison Disease is the Correct Answer:** Addison disease (primary adrenal insufficiency) is characterized by a deficiency in mineralocorticoids and glucocorticoids. This leads to **hypovolemia** (due to salt wasting), decreased vascular tone, and reduced cardiac contractility. Consequently, patients present with **low cardiac output** and hypotension, making it the "least likely" to cause a high-output state. **Analysis of Incorrect Options:** * **Thiamine Deficiency (Wet Beriberi):** Thiamine is a cofactor for carbohydrate metabolism. Deficiency leads to peripheral vasodilation and increased venous return, causing classic HOHF. * **Hyperthyroidism:** Excess thyroid hormones increase metabolic demand, induce peripheral vasodilation, and have direct positive inotropic/chronotropic effects on the heart, significantly raising cardiac output. * **Paget Disease of Bone:** Extensive remodeling of bone involves the formation of multiple **microscopic arteriovenous (AV) shunts**. These shunts bypass the capillary beds, decreasing SVR and increasing venous return to the heart. **NEET-PG High-Yield Pearls:** * **Common causes of HOHF:** Anemia, Pregnancy, AV Fistulas, Beriberi, Hyperthyroidism, and Paget’s disease. * **Hemodynamic Hallmark:** Decreased SVR + Increased Cardiac Index. * **Clinical Sign:** "Warm failure" (warm extremities and bounding pulses), unlike the "cold failure" seen in typical low-output states.

Question 1

A 56-year-old man experiences episodes of severe substernal chest pain with moderate exertion, which have increased in frequency and severity over the past year. The pain is relieved by sublingual nitroglycerin. Physical examination reveals a regular pulse of 78/min, with no murmurs or gallops. Laboratory studies show creatinine, 1.1 mg/dL; glucose, 130 mg/dL; and total serum cholesterol, 223 mg/dL. Which of the following cardiac lesions is most likely present in this man?

Accepted Answer

Coronary atherosclerosis

Answer

Calcific aortic stenosis

Answer

Restrictive cardiomyopathy

Answer

Rheumatic mitral stenosis

Question 2

Which of the following conditions presents with a constant PR interval?

Accepted Answer

Second-degree atrioventricular block, Mobitz type II

Answer

First-degree atrioventricular block

Answer

Second-degree atrioventricular block, Mobitz type I

Answer

Third-degree atrioventricular block

Question 3

Which of the following is the best predictor of cardiovascular risk?

Accepted Answer

C-reactive protein (CRP)

Answer

Antichlamydial antibody

Answer

Lipoprotein (a)

Answer

Homocysteine

Question 4

A patient suffering from atherosclerosis. Which of the following is the most beneficial drug for prevention of stroke in this patient?

Accepted Answer

Aspirin

Answer

Warfarin

Answer

Low dose subcutaneous heparin

Answer

Digoxin

Question 5

Which of the following statements regarding cardiac tamponade is true?

Accepted Answer

Enlargement of the cardiac silhouette is present

Answer

Kussmaul sign is positive

Answer

Prominent y descent is observed

Answer

Electrical alternans is seen

Question 6

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 7

Which of the following is not a clinical sign associated with mitral stenosis?

Accepted Answer

Pan-systolic murmur which radiates to axilla

Answer

Malar flush

Answer

Atrial fibrillation

Answer

Tapping, undisplaced apex beat

Question 8

What is diagnostic of a fresh myocardial infarction on ECG?

Accepted Answer

ST segment elevation

Answer

QT interval prolongation

Answer

P mitrale

Answer

ST segment depression

Question 9

Positive hepatojugular reflux is found in which of the following conditions?

Accepted Answer

Tricuspid regurgitation

Answer

Left heart failure

Answer

Decreased afterload

Answer

Decreased capillary bed pressure

Question 10

Which of the following disorders is LEAST likely to cause high output failure?

Accepted Answer

Addison disease

Answer

Thiamine deficiency

Answer

Hyperthyroidism

Answer

Paget disease of bone

Cardiology — MCQs

Cardiology — MCQs

On this page

Practice by Chapter

Want unlimited practice?