Cardiology Practice Questions

Q: Carotid sinus massage will terminate which of the following arrhythmias?

Supraventricular tachycardia. The correct answer is **Supraventricular Tachycardia (SVT)**, specifically Paroxysmal SVT (AVNRT or AVRT). [1] **Mechanism:** Carotid sinus massage (CSM) is a vagal maneuver that stimulates baroreceptors in the carotid sinus. This increases vagal (parasympathetic) tone to the heart, which slows conduction and increases the refractory period of the **Atrioventricular (AV) node**. [1] Since the most common forms of SVT (like AVNRT) involve a re-entry circuit that includes the AV node as a critical limb, the sudden delay in conduction can "break" the circuit and abruptly terminate the arrhythmia, restoring normal sinus rhythm. [1] **Analysis of Incorrect Options:** * **Atrial Flutter (A) and Atrial Fibrillation (B):** CSM increases the AV block, which may transiently slow the ventricular rate (making the underlying flutter waves or fibrillatory activity more visible on an ECG), but it **cannot terminate** these arrhythmias because the pathology originates in the atria, not the AV node. [1] * **Supraventricular Arrhythmia (C):** This is a broad category that includes AFib and Flutter. While SVT is a type of supraventricular arrhythmia, the term is too non-specific compared to SVT, which is the classic indication for termination via vagal maneuvers. **High-Yield Clinical Pearls for NEET-PG:** * **First-line management:** Vagal maneuvers (CSM or Valsalva) are the initial treatment for stable SVT. * **Drug of choice:** If vagal maneuvers fail, **Adenosine** (6mg IV rapid bolus) is the pharmacological treatment of choice. [1] * **Contraindication:** Never perform CSM if a carotid bruit is present or if there is a history of TIA/Stroke in the past 3 months to avoid dislodging an atheromatous plaque. * **Diagnostic use:** CSM can help differentiate SVT from Atrial Flutter by transiently slowing the rate to reveal "saw-tooth" waves. [2]

Q: A 62-year-old man with underlying COPD develops a viral upper respiratory infection and begins taking an over-the-counter decongestant. Shortly thereafter he experiences palpitations and presents to the emergency room, where the following rhythm strip is obtained. What is the most likely diagnosis?

Atrial flutter with 4:1 atrioventricular block. ***Atrial flutter with 4:1 atrioventricular block*** - Characteristic **sawtooth F waves** at ~300 bpm with 4:1 conduction producing a ventricular rate of ~75 bpm, consistent with **atrial flutter**. - **COPD patients** are predisposed to atrial arrhythmias, and **sympathomimetic decongestants** can trigger these rhythm disturbances. *Normal sinus rhythm* - Would show regular **P waves** preceding each QRS complex at a rate of 60-100 bpm without **sawtooth pattern**. - Palpitations and the clinical context (COPD + decongestant use) make normal rhythm unlikely. *Junctional rhythm* - Characterized by **absent or inverted P waves** and a narrow QRS complex at 40-60 bpm. - Does not explain the **sawtooth pattern** or the specific ventricular rate pattern seen in this case. *Paroxysmal supraventricular tachycardia (SVT) with 2:1 atrioventricular block* - SVT typically presents with **narrow QRS tachycardia** at rates >150 bpm, not the slower rate described. - 2:1 block would produce a different **P wave to QRS ratio** and lacks the characteristic **sawtooth appearance** of atrial flutter.

Q: Which one of the following findings is NOT associated with left-sided heart failure?

Hepatojugular reflux. ### Explanation **1. Why Hepatojugular Reflux (HJR) is the Correct Answer:** Hepatojugular reflux is a clinical sign of **Right-Sided Heart Failure (RHF)**. It occurs when manual pressure over the liver increases venous return to a failing right ventricle that cannot compensate, leading to a sustained rise in the Jugular Venous Pressure (JVP). While chronic left-sided heart failure (LHF) can eventually lead to RHF (the most common cause), HJR specifically reflects right ventricular dysfunction or systemic venous congestion, not isolated LHF [2]. **2. Analysis of Incorrect Options (Findings associated with LHF):** * **Pulmonary Edema (Option A):** In LHF, the left ventricle fails to pump blood forward, causing increased pressure in the left atrium and pulmonary veins. This hydrostatic pressure forces fluid into the alveoli, leading to pulmonary edema [1]. * **Paroxysmal Nocturnal Dyspnea (Option C):** This is a classic symptom of LHF. When a patient lies flat, interstitial fluid from the lower extremities is redistributed into the central circulation. A failing left ventricle cannot handle this increased preload, resulting in acute pulmonary congestion at night [2]. * **Prerenal Azotemia (Option D):** LHF causes a "forward failure" state with decreased cardiac output. This leads to reduced renal perfusion, triggering an increase in Blood Urea Nitrogen (BUN) and Creatinine, known as prerenal azotemia [3]. **3. Clinical Pearls for NEET-PG:** * **Most common cause of RHF:** Left-sided heart failure [2]. * **Earliest symptom of LHF:** Exertional dyspnea [2]. * **Specific sign of LHF:** Pulsus alternans (alternating strong and weak peripheral pulses). * **HJR Technique:** Apply firm pressure over the RUQ for 10–30 seconds; a positive result is a sustained rise in JVP >3 cm. It is highly suggestive of an elevated Pulmonary Capillary Wedge Pressure (PCWP).

Q: A 30-year-old man presents with recurrent attacks of feeling dizzy. An ECG was performed. What is the most likely diagnosis?

Mobitz I heart block. ***Mobitz I heart block*** - **Progressive PR interval prolongation** followed by a **dropped QRS complex** (Wenckebach phenomenon) is the classic ECG pattern of Mobitz I block. - Often **benign and vagally mediated** in young patients, causing intermittent dizziness when beats are dropped but rarely requiring intervention. *Atrial fibrillation* - ECG shows **irregularly irregular rhythm** with **absent P waves** and **fibrillatory waves**. - Would present with **palpitations** and **irregular pulse**, not episodic dizziness with normal sinus rhythm between episodes. *Paroxysmal Supraventricular Tachycardia (PSVT)* - ECG during episodes shows **narrow QRS tachycardia** (usually >150 bpm) with **regular rhythm**. - Presents with **sudden onset palpitations** and **rapid heart rate**, not gradual dizziness with bradycardia. *Complete heart block* - ECG shows **complete AV dissociation** with **independent P waves and QRS complexes** at different rates. - Would cause **severe bradycardia** (30-40 bpm) with **syncope** rather than just dizziness, and requires immediate pacemaker intervention.

Q: What is the most common cause of sudden cardiac death?

Ventricular fibrillation. ### Explanation **1. Why Ventricular Fibrillation (VF) is Correct:** Sudden Cardiac Death (SCD) is most commonly triggered by a lethal cardiac arrhythmia. Among these, **Ventricular Fibrillation (VF)** is the most frequent terminal rhythm, accounting for approximately 75–80% of cases [2]. In VF, the ventricles quiver rapidly and irregularly instead of pumping blood [1], leading to an immediate loss of cardiac output, circulatory collapse, and death within minutes if not defibrillated [3]. The most common underlying structural cause leading to VF is **Coronary Artery Disease (CAD)**, particularly acute myocardial ischemia or scarring from a previous infarct. **2. Why the Other Options are Incorrect:** * **Atrial Fibrillation (AF):** While AF is the most common sustained arrhythmia, it involves the atria. It increases the risk of stroke (embolic events) and heart failure but is rarely a direct cause of sudden death as the AV node protects the ventricles from the rapid atrial rate. * **PSVT:** These are typically narrow-complex tachycardias (like AVNRT). While they cause palpitations, dizziness, or syncope, they are almost never life-threatening in patients with normal heart structures. * **A-V Block:** While complete heart block (3rd degree) can cause asystole or severe bradycardia leading to death, it is a much less common cause of SCD compared to tachyarrhythmias like VF. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common underlying pathology for SCD:** Coronary Artery Disease (CAD). * **Most common cause of SCD in young athletes (<35 years):** Hypertrophic Cardiomyopathy (HCM). * **The "Golden Hour":** Survival rates for VF decrease by 7–10% for every minute that passes without defibrillation [2]. * **Primary Prevention:** In patients with low Ejection Fraction (<35%), an Implantable Cardioverter Defibrillator (ICD) is the treatment of choice to prevent SCD.

Q: The Bundle of Kent is associated with which of the following conditions?

Wolff-Parkinson-White syndrome. **Wolff-Parkinson-White (WPW) syndrome** is the correct answer because it is characterized by the presence of an accessory pathway known as the **Bundle of Kent** [1]. In a normal heart, the AV node is the only electrical bridge between the atria and ventricles. In WPW, the Bundle of Kent bypasses the AV node, leading to **pre-excitation** of the ventricles [2]. This results in the classic ECG triad: 1. **Short PR interval** ( 0.12s) [1]. **Analysis of Incorrect Options:** * **Sick Sinus Syndrome:** Refers to SA node dysfunction leading to alternating bradycardia and tachycardia (Tachy-Brady syndrome); it does not involve accessory pathways. * **Lown-Ganong-Levine (LGL) Syndrome:** Associated with the **James fibers** (intranodal accessory pathway). It presents with a short PR interval but a **normal QRS** (no delta wave) [1]. * **Stokes-Adams Syndrome:** Refers to sudden syncope caused by a complete heart block or severe arrhythmia leading to decreased cardiac output. **High-Yield Clinical Pearls for NEET-PG:** * **Drug Contraindication:** Avoid **ABCD** (Atropine/Adenosine, Beta-blockers, Calcium channel blockers, Digoxin) in WPW with Atrial Fibrillation, as they block the AV node and may force conduction through the Bundle of Kent, risking Ventricular Fibrillation [2]. * **Treatment of Choice:** Radiofrequency ablation of the accessory pathway. * **Association:** WPW syndrome is sometimes associated with **Ebstein’s anomaly**.

Q: Giant a waves in JVP are seen in which of the following conditions?

Complete heart block. **Explanation:** The **'a' wave** in the Jugular Venous Pulse (JVP) represents **atrial contraction**. Under normal circumstances, the right atrium contracts when the tricuspid valve is open, pushing blood into the right ventricle. **Giant 'a' waves** (also known as Cannon 'a' waves) occur when the right atrium contracts against a **closed tricuspid valve**. In **Complete Heart Block (3rd-degree AV block)**, there is total AV dissociation [3]. The atria and ventricles beat independently [2]. Occasionally, the P-wave (atrial contraction) coincides with the QRS complex (ventricular contraction/systole). When this happens, the atrium contracts against a closed tricuspid valve, causing a massive backflow of pressure into the jugular vein, visible as a "cannon" wave. **Analysis of Incorrect Options:** * **Tachycardia:** Generally shortens the filling time but does not inherently cause AV dissociation or contraction against a closed valve. * **Atrial Ectopic:** While it may cause a slightly prominent 'a' wave if it occurs early, it does not typically produce the classic "giant" or "cannon" waves seen in dissociation. * **1st Degree Heart Block:** Here, every atrial impulse is conducted to the ventricle, just with a delay (prolonged PR interval) [1]. Since the tricuspid valve is open during atrial contraction, it results in a **soft/small 'a' wave**, not a giant one. **High-Yield Clinical Pearls for NEET-PG:** * **Regular Cannon 'a' waves:** Seen in Junctional Rhythm or SVT (Atrial and ventricular contraction are synchronized). * **Irregular Cannon 'a' waves:** Pathognomonic for **Complete Heart Block** or Ventricular Tachycardia (due to AV dissociation) [3]. * **Absent 'a' waves:** Seen in **Atrial Fibrillation** (no coordinated atrial contraction). * **Prominent/Large 'a' waves (not cannon):** Seen in Right Ventricular Hypertrophy, Tricuspid Stenosis, and Pulmonary Hypertension (atrium pushing against a stiff/obstructed valve).

Question 1

Carotid sinus massage will terminate which of the following arrhythmias?

Accepted Answer

Supraventricular tachycardia

Answer

Atrial flutter

Answer

Atrial fibrillation

Answer

Supraventricular arrhythmia

Question 2

A patient with angina, exertional syncope, and left ventricular hypertrophy is diagnosed with aortic stenosis. What is the predicted lifespan of this patient?

Accepted Answer

3 years

Answer

1 year

Answer

2 years

Answer

4 years

Question 3

Unequal pulses in upper and lower extremities (i.e., radio-femoral delay) is/are seen in which of the following conditions?

Accepted Answer

Post-ductal coarctation of the aorta

Answer

Aortic dissection

Answer

Supra-valvular aortic stenosis

Answer

Sub-valvular aortic stenosis

Question 4

A 70-year-old male patient presented to the emergency department with pain in the epigastrium and difficulty in breathing for 6 hours. On examination, his heart rate was 56 beats per minute and the blood pressure was 106/60 mm Hg. Chest examination was normal. The patient has been taking omeprazole for gastroesophageal reflux disease for the last 6 months. What should be the initial investigation?

Accepted Answer

An ECG

Answer

An upper GI endoscopy

Answer

Urgent ultrasound of the abdomen

Answer

An x-ray chest

Question 5

A 62-year-old man with underlying COPD develops a viral upper respiratory infection and begins taking an over-the-counter decongestant. Shortly thereafter he experiences palpitations and presents to the emergency room, where the following rhythm strip is obtained. What is the most likely diagnosis?

Accepted Answer

Atrial flutter with 4:1 atrioventricular block

Answer

Normal sinus rhythm

Answer

Junctional rhythm

Answer

Paroxysmal supraventricular tachycardia (SVT) with 2:1 atrioventricular block

Question 6

Which one of the following findings is NOT associated with left-sided heart failure?

Accepted Answer

Hepatojugular reflux

Answer

Pulmonary edema

Answer

Paroxysmal nocturnal dyspnea

Answer

Prerenal azotemia

Question 7

A 30-year-old man presents with recurrent attacks of feeling dizzy. An ECG was performed. What is the most likely diagnosis?

Accepted Answer

Mobitz I heart block

Answer

Atrial fibrillation

Answer

Paroxysmal Supraventricular Tachycardia (PSVT)

Answer

Complete heart block

Question 8

What is the most common cause of sudden cardiac death?

Accepted Answer

Ventricular fibrillation

Answer

Atrial fibrillation

Answer

Paroxysmal supraventricular tachycardia (PSVT)

Answer

Atrioventricular (A-V) block

Question 9

The Bundle of Kent is associated with which of the following conditions?

Accepted Answer

Wolff-Parkinson-White syndrome

Answer

Sick sinus syndrome

Answer

Long-Ganong-Levine syndrome

Answer

Stokes-Adams syndrome

Question 10

Giant a waves in JVP are seen in which of the following conditions?

Accepted Answer

Complete heart block

Answer

Tachycardia

Answer

Atrial ectopic

Answer

1st degree heart block

Cardiology — MCQs

Cardiology — MCQs

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