Cardiology Practice Questions

Q: Loud S1 is present in which of the following conditions?

Mitral stenosis with a pliable valve. The intensity of the first heart sound (S1) is primarily determined by the velocity and force of the closure of the Mitral (M1) and Tricuspid (T1) valves. **Why Option A is Correct:** In **Mitral Stenosis (MS)**, the elevated left atrial pressure keeps the mitral leaflets wide apart until the very end of diastole. When ventricular systole begins, the leaflets must travel a greater distance to close, slamming shut with high velocity, which creates a **loud (accentuated) S1** [2]. However, this requires the leaflets to be **pliable** (mobile). **Why the other options are incorrect:** * **B. Mitral stenosis with a calcified valve:** If the valve leaflets become rigid, fibrosed, or heavily calcified, their mobility is restricted. They cannot "snap" shut, leading to a **soft or muffled S1** [1]. * **C. Mitral regurgitation:** In chronic MR, the leaflets often fail to appose properly or are structurally damaged, leading to a **soft S1**. * **D. Aortic stenosis:** S1 is produced by the AV valves (Mitral/Tricuspid). Aortic stenosis primarily affects the second heart sound (S2), often causing a soft A2 or paradoxical splitting. **High-Yield Clinical Pearls for NEET-PG:** * **Loud S1 Causes:** Mitral Stenosis (pliable valve), Tachycardia, Short PR interval (WPW syndrome), and Hyperdynamic states (Anemia, Pregnancy, Thyrotoxicosis) [2]. * **Soft S1 Causes:** Mitral Regurgitation, Calcified MS, Long PR interval (1st-degree heart block), and Obesity/COPD (due to sound dampening). * **Variable S1:** Characteristic of **Atrial Fibrillation** and **Complete Heart Block** (Cannon sounds). * In MS, a loud S1 and an **Opening Snap** are clinical indicators that the valve is still mobile and potentially amenable to Valvotomy [1], [2].

Q: A 46-year-old female presents to casualty with chest pain. Her BP is 140/80mmHg, heart rate is 90bpm, and saturations are 99% on room air. What should be your next step?

Perform a 12-lead ECG. **Explanation:** In any patient presenting with acute chest pain, the primary objective is to rule out life-threatening conditions, most importantly **Acute Coronary Syndrome (ACS)** [1]. **1. Why Option D is Correct:** The **12-lead Electrocardiogram (ECG)** is the gold-standard initial diagnostic tool for chest pain [1]. According to AHA/ESC guidelines, an ECG should be performed and interpreted within **10 minutes** of arrival at the emergency department. It is essential for differentiating between ST-elevation myocardial infarction (STEMI), NSTEMI, or non-cardiac causes, which dictates the entire management pathway (e.g., immediate reperfusion vs. further observation) [2]. **2. Why Other Options are Incorrect:** * **Option A (Oxygen):** Routine oxygen administration is no longer recommended unless the patient is hypoxic (SpO2 <90-94%). This patient has a saturation of 99%, making oxygen unnecessary and potentially harmful due to hyperoxia-induced vasoconstriction. * **Option B (Analgesia):** While pain relief is important, it should not precede diagnosis. Masking pain with analgesics (like morphine) before an ECG can delay the recognition of an evolving MI. * **Option C (Aspirin):** Although aspirin is a cornerstone of ACS management, it is administered *after* or *concurrently* with the initial assessment. The ECG remains the absolute priority to establish the diagnosis. **High-Yield Clinical Pearls for NEET-PG:** * **Door-to-ECG time:** <10 minutes. * **Door-to-Balloon time (PCI):** <90 minutes. * **Door-to-Needle time (Thrombolysis):** <30 minutes. * In females, diabetics, and the elderly, chest pain may be absent; always maintain a high index of suspicion for "atypical presentations" (dyspnea, epigastric pain) [3].

Q: Acute aortic regurgitation occurs in-

Infective endocarditis. **Explanation:** **Aortic Regurgitation (AR)** can be classified into acute and chronic forms based on the speed of onset and the heart's compensatory mechanisms. **Why Infective Endocarditis (IE) is correct:** Infective endocarditis is the most common cause of **acute** aortic regurgitation [1]. The mechanism involves rapid destruction of the valve leaflets or the development of a perforation/vegetation that prevents proper coaptation [1]. Because the left ventricle (LV) does not have time to dilate and accommodate the sudden volume overload, LV end-diastolic pressure rises sharply, leading to rapid-onset pulmonary edema and cardiogenic shock [1]. **Why the other options are incorrect:** * **Ankylosing Spondylitis (B):** This causes **chronic** AR due to aortitis and thickening of the aortic root, leading to gradual valve distortion. * **Marfan’s Syndrome (C):** This is a classic cause of **chronic** AR. It results from cystic medial necrosis leading to progressive aortic root dilation (aneurysm) and secondary valvular insufficiency. * **Rheumatoid Arthritis (D):** This is a rare cause of **chronic** AR, typically occurring due to rheumatoid nodules on the valve or non-specific aortitis. **High-Yield Clinical Pearls for NEET-PG:** * **Acute AR Causes:** Infective Endocarditis, Aortic Dissection (Type A), and Chest Trauma [1]. * **Physical Exam:** In acute AR, the classic "wide pulse pressure" and "Austin Flint murmur" may be **absent** because the LV cannot dilate [1]. The pulse pressure is often normal or narrow due to low stroke volume. * **Management:** Acute AR is a surgical emergency. **Beta-blockers are contraindicated** in acute AR (as they block the compensatory tachycardia needed to maintain cardiac output), whereas they are used in chronic AR/dissection.

Q: Reversed splitting of S2 heart sound is heard in which of the following conditions?

Left bundle branch block. ### Explanation The second heart sound (S2) consists of two components: **A2** (Aortic valve closure) and **P2** (Pulmonary valve closure). Normally, A2 precedes P2, and the gap increases during inspiration (physiological splitting) [2]. **Reversed (paradoxical) splitting** occurs when P2 precedes A2. This happens when there is a significant delay in the closure of the aortic valve. **Why Option D is Correct:** In **Left Bundle Branch Block (LBBB)**, electrical activation of the left ventricle is delayed. This results in delayed mechanical contraction and prolonged ejection time of the left ventricle, causing the aortic valve to close *after* the pulmonary valve. During inspiration, P2 moves later (closer to A2), narrowing the split; during expiration, P2 moves earlier, widening the split—the opposite of normal physiology. **Analysis of Incorrect Options:** * **A. Ventricular Septal Defect (VSD):** Typically causes a **wide, fixed S2** (if large) or a normal split. It does not delay A2 enough to cause reversal. * **B. Right Bundle Branch Block (RBBB):** Causes a **wide physiological split**. Delay in right ventricular activation delays P2, increasing the distance between A2 and P2. * **C. Acute Pulmonary Embolism:** Leads to right ventricular strain and delayed P2, resulting in a **wide physiological split**, not reversed. **High-Yield Clinical Pearls for NEET-PG:** * **Causes of Reversed Splitting:** LBBB, Aortic Stenosis (severe), Hypertrophic Obstructive Cardiomyopathy (HOCM), and Left Ventricular failure [1]. * **Wide Fixed Splitting:** Pathognomonic for **Atrial Septal Defect (ASD)**. * **Wide Physiological Splitting:** Seen in RBBB, Pulmonary Stenosis, and Mitral Regurgitation. * **Mnemonic for Reversed Split:** "**A**lways **L**earn **H**eart **S**ounds" (**A**ortic Stenosis, **L**BBB, **H**OCM, **S**ystolic Hypertension).

Q: What is true regarding a second-degree heart block?

The ventricular rate is slower than the atrial rate.. ### Explanation **1. Why Option D is Correct:** In second-degree heart block, some atrial impulses (P waves) fail to conduct to the ventricles. This results in "dropped beats," where a P wave is not followed by a QRS complex [1]. Because every atrial contraction does not result in a ventricular contraction, the **atrial rate (PP interval) will always be higher than the ventricular rate (RR interval)**. This is the hallmark of all partial heart blocks (Mobitz Type I and Type II). **2. Why Other Options are Incorrect:** * **Option A:** This is incorrect because second-degree block is an **incomplete** block. Complete heart block refers to Third-degree heart block, where there is total AV dissociation. * **Option B:** Idioventricular rhythm occurs in **Third-degree (complete) heart block**, where a distal pacemaker takes over because no impulses from the atria reach the ventricles [2]. In second-degree block, the rhythm is usually conducted from the SA node, albeit intermittently. * **Option C:** While severe bradycardia can cause syncope, **Stokes-Adams attacks** (sudden collapse due to asystole or ventricular fibrillation) are classically associated with **Third-degree heart block** [3] or advanced Mobitz Type II block. **3. Clinical Pearls for NEET-PG:** * **Mobitz Type I (Wenckebach):** Characterized by progressive PR interval lengthening until a beat is dropped [1]. Usually localized at the **AV node** and has a benign prognosis. * **Mobitz Type II:** Constant PR interval followed by a sudden dropped QRS [1]. Usually localized **infra-nodal (Bundle of His)** and carries a high risk of progressing to complete heart block; often requires a permanent pacemaker. * **Vagal Maneuvers:** Carotid sinus massage worsens Mobitz Type I (slows AV node) but may improve Mobitz Type II (slows sinus rate, allowing the His-Purkinje system more time to recover).

Q: When should prophylactic antibiotics be administered to a patient with rheumatic heart disease undergoing dental treatment?

1 hour before the procedure. ### Explanation The primary goal of antibiotic prophylaxis in patients with structural heart disease (like Rheumatic Heart Disease) undergoing invasive procedures is to prevent **Infective Endocarditis (IE)**. **1. Why Option C is Correct:** To be effective, the antibiotic must reach its **peak serum concentration** at the exact time of the procedure (when the transient bacteremia occurs). For oral medications, this typically takes about 1 hour. According to the current AHA (American Heart Association) and IDSA guidelines, prophylactic antibiotics should be administered **30 to 60 minutes before** the procedure. This ensures maximum bactericidal activity during the period of highest risk. **2. Why the Other Options are Incorrect:** * **Option A (3 hours before):** By this time, the serum concentration of many antibiotics (like Amoxicillin) may already be declining, providing suboptimal protection. * **Option D (1 day before):** Administering antibiotics 24 hours early is ineffective and may lead to the development of resistant oral flora before the procedure begins. * **Option B (7 days before):** Long-term administration is reserved for secondary prophylaxis of Rheumatic Fever, not for the prevention of IE during dental procedures. **3. NEET-PG High-Yield Pearls:** * **Drug of Choice:** Oral **Amoxicillin (2g)** is the first-line agent for dental prophylaxis. * **Penicillin Allergy:** If the patient is allergic to Penicillin, use **Clindamycin (600mg)**, Azithromycin, or Clarithromycin (500mg). * **Indications:** Prophylaxis is only recommended for "high-risk" cardiac conditions (e.g., prosthetic valves, previous IE, cyanotic congenital heart disease) undergoing procedures involving **gingival manipulation** or perforation of the oral mucosa. * **Missed Dose:** If the antibiotic was not administered before the procedure, it may be given up to **2 hours after** the procedure, though pre-procedure is preferred.

Question 1

What is the treatment of choice in ventricular fibrillation?

Accepted Answer

Cardioversion

Answer

Sotalol

Answer

Ibutilide

Answer

Adenosine

Question 2

Which of the following features on X-ray chest can differentiate an Atrial Septal Defect (ASD) from a Ventricular Septal Defect (VSD)?

Accepted Answer

Enlarged Left Atrium

Answer

Pulmonary Plethora

Answer

Enlarged Pulmonary Artery

Answer

Enlarged Aorta

Question 3

Loud S1 is present in which of the following conditions?

Accepted Answer

Mitral stenosis with a pliable valve

Answer

Mitral stenosis with a calcified valve

Answer

Mitral regurgitation

Answer

Aortic stenosis

Question 4

A 46-year-old female presents to casualty with chest pain. Her BP is 140/80mmHg, heart rate is 90bpm, and saturations are 99% on room air. What should be your next step?

Accepted Answer

Perform a 12-lead ECG

Answer

Administer oxygen

Answer

Administer analgesia

Answer

Give aspirin 300mg

Question 5

Left-sided endocarditis is most commonly associated with which of the following cardiac conditions?

Accepted Answer

Patent foramen ovale

Answer

Endocardial cushion defect

Answer

Atrial septal defect of the secundum type

Answer

Atrial septal defect of the primum type

Question 6

Acute aortic regurgitation occurs in-

Accepted Answer

Infective endocarditis

Answer

Ankylosing spondylitis

Answer

Marfan's syndrome

Answer

Rheumatoid arthritis

Question 7

Reversed splitting of S2 heart sound is heard in which of the following conditions?

Accepted Answer

Left bundle branch block

Answer

Ventricular septal defect

Answer

Right bundle branch block

Answer

Acute pulmonary embolism

Question 8

Diastolic heart failure is impairment in the filling of the left ventricle. Which of the following is LEAST likely to occur?

Accepted Answer

Improvement of the patient’s condition with administration of a positive inotropic agent

Answer

Improvement of the patient’s condition with administration of a calcium channel blocker

Answer

Decreased compliance of the heart

Answer

Increased left atrial pressure

Question 9

What is true regarding a second-degree heart block?

Accepted Answer

The ventricular rate is slower than the atrial rate.

Answer

It is a complete heart block.

Answer

It gives rise to idioventricular rhythm.

Answer

It is responsible for Stokes-Adam's syndrome.

Question 10

When should prophylactic antibiotics be administered to a patient with rheumatic heart disease undergoing dental treatment?

Accepted Answer

1 hour before the procedure

Answer

3 hours before the procedure

Answer

7 days before the procedure

Answer

1 day before the procedure

Cardiology — MCQs

Cardiology — MCQs

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