Cardiology — MCQs
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All of the following may be seen in ventricular premature beats, EXCEPT?
Which one of the following electrocardiographic changes is found in hypercalcemia?
Which of the following conditions causes a wide pulse pressure?
An 18-year-old man is admitted to the hospital with acute onset of substernal chest pain that began abruptly 30 minutes ago. The pain radiates to his neck and right arm. He has otherwise been in good health. On physical examination, he is diaphoretic and tachypnoeic. His BP is 102/48 mmHg and heart rate is 112 bpm, with a regular rhythm but is tachycardiac. A 2/6 holosystolic murmur is heard best at the apex and radiates to the axilla. His lungs have bilateral rales at the bases. The ECG demonstrates 4 mm of ST elevation in the anterior leads. In the past, he was hospitalized for some problem with his heart when he was 4 years old. His mother, who accompanies him, reports that he received aspirin and gamma globulin as treatment. Since that time, he has required intermittent follow-up with echocardiography. What is the most likely cause of this patient's acute coronary syndrome?
Which of the following diastolic sounds may be heard during cardiac auscultation?
What is the most important drug in the treatment of Ischemic Heart Disease?
Which infective organism is a known cause of atrioventricular block?
Which of the following findings is NOT seen in primary pulmonary hypertension?
What is the best treatment for multifocal atrial tachycardia?
All of the following are true regarding hypertrophic obstructive cardiomyopathy, except?
Cardiology Indian Medical PG Practice Questions and MCQs
Question 271: All of the following may be seen in ventricular premature beats, EXCEPT?
- A. Fusion beat
- B. Narrow QRS complex (Correct Answer)
- C. AV Dissociation
- D. Wide QRS complex
Explanation: Ventricular Premature Beats (VPBs), also known as Premature Ventricular Contractions (PVCs), originate from an ectopic focus within the ventricular myocardium or the Purkinje system, distal to the Bundle of His. [1] **Why "Narrow QRS complex" is the correct answer:** In a VPB, the electrical impulse originates in the ventricles and spreads through the myocardium via slow cell-to-cell conduction rather than the rapid specialized His-Purkinje system. This slow depolarization results in a **Wide QRS complex (typically >0.12 seconds)** with a bizarre morphology. [1] A narrow QRS complex indicates that ventricular depolarization occurred rapidly through the normal conduction system, which is characteristic of supraventricular beats, not ventricular ones. **Analysis of other options:** * **Wide QRS complex:** This is the hallmark of VPBs due to the slow, non-sequential activation of the ventricles. [1] * **AV Dissociation:** Since the beat originates in the ventricle, the sinus node often continues to fire independently, or there may be retrograde block, leading to a lack of relationship between P waves and the premature QRS. [1] * **Fusion beat:** This occurs when a supraventricular impulse and a ventricular ectopic impulse activate the ventricles simultaneously. [1] The resulting QRS complex has a morphology intermediate between a normal beat and a VPB. **Clinical Pearls for NEET-PG:** * **Compensatory Pause:** VPBs are usually followed by a *complete* compensatory pause (the distance between the pre-PVC and post-PVC R waves is equal to two normal R-R intervals). [2] * **T-wave polarity:** The T-wave in a VPB is typically large and oriented in the opposite direction (discordant) to the main QRS deflection. * **Rule of Bigeminy:** When every alternate beat is a VPB, it is termed ventricular bigeminy. * **Malignant VPBs:** VPBs are considered concerning if they are frequent (>10/hour), multifocal, occur in runs (NSVT), or exhibit the **'R-on-T' phenomenon**, which can trigger Ventricular Fibrillation. [3]
Question 272: Which one of the following electrocardiographic changes is found in hypercalcemia?
- A. Prolonged Q-T interval
- B. Short Q-T interval (Correct Answer)
- C. Increased QRS interval
- D. Short P-R interval
Explanation: The correct answer is **Short Q-T interval**. **Mechanism:** The QT interval on an ECG represents the total duration of ventricular depolarization and repolarization. In **hypercalcemia**, the increased extracellular calcium concentration shortens the duration of the action potential plateau (Phase 2) by accelerating calcium influx. This leads to faster ventricular repolarization, which manifests on the ECG as a shortened ST segment and, consequently, a **shortened QT interval**. **Analysis of Incorrect Options:** * **A. Prolonged Q-T interval:** This is a classic finding in **hypocalcemia**. Low calcium levels delay Phase 2 of the action potential, lengthening the ST segment. * **C. Increased QRS interval:** Widening of the QRS complex is typically associated with hyperkalemia, bundle branch blocks, or tricyclic antidepressant (TCA) toxicity, rather than calcium imbalances [1]. * **D. Short P-R interval:** A short PR interval is characteristic of pre-excitation syndromes like Wolff-Parkinson-White (WPW) syndrome [2] or Lown-Ganong-Levine (LGL) syndrome [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Osborn Waves (J waves):** While most commonly associated with hypothermia, they can occasionally be seen in severe hypercalcemia. * **Severe Hypercalcemia:** Can lead to T-wave flattening or inversion, and in extreme cases, may mimic an acute myocardial infarction (pseudoinfarction pattern). * **Mnemonic:** "Short Cow (Ca) = Short QT" and "Long Cow (Ca) = Long QT." * **Digoxin Toxicity:** Also causes a shortened QT interval; however, it is distinguished by the characteristic "reverse tick" or "scooped" ST-segment depression.
Question 273: Which of the following conditions causes a wide pulse pressure?
- A. Aortic stenosis
- B. Aortic regurgitation (Correct Answer)
- C. Mitral stenosis
- D. Tricuspid stenosis
Explanation: **Explanation:** **Pulse pressure** is the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP). A **wide pulse pressure** occurs when there is either an increase in stroke volume or a decrease in peripheral vascular resistance/arterial compliance [1]. **Why Aortic Regurgitation (AR) is the Correct Answer:** In AR, blood flows back from the aorta into the left ventricle during diastole [3]. This leads to: 1. **Increased SBP:** The left ventricle handles an increased stroke volume (normal venous return + regurgitant volume), ejecting more blood into the aorta [1]. 2. **Decreased DBP:** The rapid "runoff" of blood back into the ventricle and into the peripheral circulation causes a significant drop in diastolic pressure. The combination of high SBP and low DBP results in a characteristically wide pulse pressure. **Why Other Options are Incorrect:** * **Aortic Stenosis (AS):** Causes a **narrow pulse pressure** (*pulsus parvus et tardus*). The obstructed outflow reduces stroke volume, leading to a low systolic pressure [2]. * **Mitral Stenosis (MS) & Tricuspid Stenosis (TS):** These conditions limit ventricular filling, which reduces stroke volume and cardiac output, typically resulting in a narrow or normal pulse pressure [4]. **High-Yield Clinical Pearls for NEET-PG:** * **Water-hammer pulse (Corrigan’s pulse):** A rapid upstroke and collapse of the carotid pulse, pathognomonic for AR [1]. * **Traube’s sign:** "Pistol shot" sounds heard over the femoral arteries. * **Duroziez’s sign:** A systolic and diastolic murmur heard over the femoral artery when compressed. * **Other causes of wide pulse pressure:** Thyrotoxicosis, Patent Ductus Arteriosus (PDA), Anemia, Beriberi, and Atherosclerosis (due to stiffened arteries).
Question 274: An 18-year-old man is admitted to the hospital with acute onset of substernal chest pain that began abruptly 30 minutes ago. The pain radiates to his neck and right arm. He has otherwise been in good health. On physical examination, he is diaphoretic and tachypnoeic. His BP is 102/48 mmHg and heart rate is 112 bpm, with a regular rhythm but is tachycardiac. A 2/6 holosystolic murmur is heard best at the apex and radiates to the axilla. His lungs have bilateral rales at the bases. The ECG demonstrates 4 mm of ST elevation in the anterior leads. In the past, he was hospitalized for some problem with his heart when he was 4 years old. His mother, who accompanies him, reports that he received aspirin and gamma globulin as treatment. Since that time, he has required intermittent follow-up with echocardiography. What is the most likely cause of this patient's acute coronary syndrome?
- A. Dissection of the aortic root and left coronary ostia
- B. Presence of a myocardial bridge overlying the left anterior descending artery
- C. Thrombosis of a coronary artery aneurysm (Correct Answer)
- D. Vasospasm following cocaine ingestion
Explanation: ### Explanation **Correct Answer: C. Thrombosis of a coronary artery aneurysm** The clinical presentation describes an 18-year-old male with an **Acute Anterior Wall Myocardial Infarction (STEMI)**, evidenced by substernal chest pain, diaphoresis [1], and 4 mm ST-elevation in anterior leads. The presence of bilateral rales (lung crepitations) [1], [1] and a holosystolic murmur (acute mitral regurgitation) suggests acute heart failure/papillary muscle dysfunction [1]. The crucial diagnostic clue is the childhood history: hospitalization at age 4 treated with **Aspirin and IV Gamma Globulin (IVIG)**. This is the classic treatment for **Kawasaki Disease (KD)**. KD is a medium-vessel vasculitis that can lead to **coronary artery aneurysms (CAAs)** in 25% of untreated cases. Even with treatment, large or giant aneurysms can persist. Over time, sluggish blood flow (stasis) within these aneurysms predisposes to **thrombus formation**, leading to acute coronary occlusion and MI in young adulthood. **Analysis of Incorrect Options:** * **A. Dissection of the aortic root:** Usually presents with "tearing" pain and is associated with Marfan syndrome or hypertension. While it can cause MI if it involves the ostia, the history of IVIG/Aspirin specifically points to KD. * **B. Myocardial bridge:** This is a congenital anomaly where a segment of a coronary artery (usually LAD) runs through the myocardium. While it can cause ischemia, it rarely presents as a massive STEMI with heart failure in this clinical context. * **D. Cocaine ingestion:** Can cause vasospasm and MI in young patients, but it does not explain the childhood history of IVIG treatment and long-term echocardiographic follow-up. **NEET-PG High-Yield Pearls:** * **Kawasaki Disease (Mucocutaneous Lymph Node Syndrome):** Most common cause of acquired heart disease in children in developed nations. * **Diagnostic Criteria (CRASH and Burn):** **C**onjunctivitis (non-purulent), **R**ash (polymorphous), **A**denopathy (cervical), **S**trawberry tongue, **H**ands/feet (edema/desquamation), and **Burn** (High-grade fever >5 days). * **Cardiac Complication:** Coronary artery aneurysms are the most feared complication; IVIG administered within 10 days of onset significantly reduces this risk.
Question 275: Which of the following diastolic sounds may be heard during cardiac auscultation?
- A. S3 (Correct Answer)
- B. S4
- C. Opening snap
- D. Ejection click
Explanation: **Explanation:** Diastolic sounds occur between S2 and S1 [2]. To identify the correct answer, one must distinguish between sounds occurring during ventricular filling (diastole) versus those occurring during ventricular contraction (systole). **Correct Answer: A. S3** The **Third Heart Sound (S3)**, also known as the ventricular gallop, occurs during the **early rapid filling phase** of diastole [2]. It is caused by blood rushing into an overfilled or dilated ventricle, hitting the ventricular wall. While it can be physiological in children and athletes, in adults, it is a hallmark of **congestive heart failure (CHF)** or volume overload states (e.g., Mitral Regurgitation). **Analysis of Other Options:** * **B. S4:** While S4 occurs at the end of diastole (atrial kick), it is technically a **pre-systolic** sound. In the context of standard NEET-PG classification, S3 is the classic "diastolic sound" associated with filling, whereas S4 is associated with atrial contraction against a stiff ventricle (e.g., LVH). * **C. Opening Snap:** This is a high-pitched diastolic sound heard in **Mitral Stenosis** [1]. However, it is an opening sound of a valve, not a heart sound produced by blood flow/vibration like S3. * **D. Ejection Click:** This is an **early systolic** sound [1]. It occurs shortly after S1 and is associated with the opening of semilunar valves (Aortic/Pulmonary) in conditions like stenosis or bicuspid aortic valve. **High-Yield NEET-PG Pearls:** * **S3 (Ventricular Gallop):** Best heard at the apex with the bell (low pitch). Associated with **systolic dysfunction**. * **S4 (Atrial Gallop):** Associated with **diastolic dysfunction** (stiff ventricle). Absent in Atrial Fibrillation. * **Sequence of Diastolic Sounds:** S2 → Opening Snap → S3 → Mid-diastolic murmur → S4 → S1 [1].
Question 276: What is the most important drug in the treatment of Ischemic Heart Disease?
- A. Statins
- B. Aspirin (Correct Answer)
- C. Beta blockers
- D. Nitrates
Explanation: **Explanation:** **Aspirin** is considered the most important drug in the management of Ischemic Heart Disease (IHD) because it is the only medication among the options that has been definitively proven to **reduce mortality** across the entire spectrum of the disease—from stable angina to Acute Coronary Syndrome (ACS) [1]. Its mechanism involves the irreversible inhibition of Cyclooxygenase-1 (COX-1), preventing the synthesis of Thromboxane A2 [2]. This inhibits platelet aggregation, thereby preventing the progression of a stable plaque into an occlusive thrombus [2]. **Analysis of Incorrect Options:** * **Statins (Option A):** While crucial for long-term plaque stabilization and secondary prevention (lowering LDL), they do not provide the immediate life-saving anti-thrombotic effect seen with Aspirin during acute events. * **Beta-blockers (Option B):** These are the first-line drugs for **symptom control** in stable angina as they reduce myocardial oxygen demand [3]. While they improve survival post-MI, they are secondary to Aspirin in overall priority. * **Nitrates (Option D):** These are primarily **venodilators** used for symptomatic relief of chest pain [1]. They have **no proven mortality benefit** in IHD. **Clinical Pearls for NEET-PG:** * **Gold Standard Dose:** In acute settings, a loading dose of 150–300 mg (chewed for faster absorption) is recommended. * **Primary vs. Secondary Prevention:** Aspirin is mandatory for secondary prevention; however, its role in primary prevention is now restricted due to bleeding risks. * **Contraindication:** In patients with true Aspirin allergy, **Clopidogrel** is the preferred alternative [1]. * **High-Yield Fact:** Aspirin reduces the risk of MI and death by approximately 25-30% in patients with unstable angina.
Question 277: Which infective organism is a known cause of atrioventricular block?
- A. Treponema pallidum
- B. Borrelia burgdorferi (Correct Answer)
- C. Cryptococcus
- D. Listeria monocytogenes
Explanation: The correct answer is **Borrelia burgdorferi**, the causative agent of **Lyme disease**. **1. Why Borrelia burgdorferi is correct:** Lyme carditis occurs in approximately 1–10% of patients during the early disseminated stage of infection [1]. The hallmark of Lyme carditis is **atrioventricular (AV) nodal conduction block**, which can range from first-degree to complete (third-degree) heart block [1]. The organism infiltrates the cardiac conduction system, causing localized inflammation (myocarditis). A classic clinical scenario is a young patient presenting with sudden-onset high-grade AV block, often preceded by erythema migrans or joint pain [1]. **2. Why the other options are incorrect:** * **Treponema pallidum:** Causes Syphilis. While tertiary syphilis can cause cardiovascular complications like **aortitis** and aortic regurgitation (due to vasa vasorum involvement), it typically does not target the AV node directly. * **Cryptococcus:** This is a fungal pathogen primarily causing meningitis or pneumonia in immunocompromised patients; it does not have a predilection for the cardiac conduction system. * **Listeria monocytogenes:** Primarily causes meningitis or sepsis, especially in neonates, the elderly, and the immunocompromised. It is not a recognized cause of heart block. **3. NEET-PG High-Yield Pearls:** * **Lyme Carditis Management:** Most AV blocks in Lyme disease are reversible with appropriate antibiotic therapy (IV Ceftriaxone or oral Doxycycline) [3]. Permanent pacemakers are rarely required [4]. * **Other Infectious Causes of AV Block:** Chagas disease (*Trypanosoma cruzi*), Diphtheria (due to exotoxin), and Viral myocarditis (e.g., Coxsackie B). * **ECG in Lyme:** Look for fluctuating degrees of AV block; it can progress rapidly from 1st degree to 3rd degree [2].
Question 278: Which of the following findings is NOT seen in primary pulmonary hypertension?
- A. Left parasternal heave
- B. Right parasternal heave (Correct Answer)
- C. Single S2
- D. Pulmonary ejection click
Explanation: In primary pulmonary hypertension (now classified under Pulmonary Arterial Hypertension), the core pathophysiology involves increased resistance in the pulmonary vasculature, leading to **Right Ventricular (RV) hypertrophy and dilatation.** [1] **Why "Right parasternal heave" is the correct answer (the finding NOT seen):** This is a classic "trick" question regarding bedside physical examination. A heave (precordial lift) caused by right ventricular enlargement is felt at the **Left Parasternal** border (3rd/4th intercostal space) [3]. There is no such clinical entity as a "Right parasternal heave" in the context of pulmonary hypertension; the heart is situated in the left hemithorax, and RV enlargement displaces the impulse toward the left sternal border, not the right. **Analysis of Incorrect Options:** * **Left parasternal heave:** This is a hallmark sign of RV hypertrophy/enlargement, which occurs as the right ventricle pumps against high pulmonary pressures [3]. * **Single S2:** In severe pulmonary hypertension, the pulmonary component (P2) becomes very loud and occurs earlier, often merging with the aortic component (A2), resulting in a single, loud S2 [1]. * **Pulmonary ejection click:** This is caused by the sudden opening of the pulmonary valve into a dilated pulmonary artery under high pressure. It is typically heard at the left upper sternal border. **High-Yield Clinical Pearls for NEET-PG:** * **P2 Intensity:** A loud P2 (palpable in the 2nd left intercostal space) is the most sensitive physical sign of pulmonary hypertension [3]. * **Graham Steell Murmur:** A high-pitched, decrescendo diastolic murmur of pulmonary regurgitation may be heard. * **ECG Findings:** Look for "P pulmonale" (tall, peaked P waves) and Right Axis Deviation [2].
Question 279: What is the best treatment for multifocal atrial tachycardia?
- A. DC shock
- B. Amiodarone
- C. Verapamil (Correct Answer)
- D. Beta blocker
Explanation: **Explanation:** Multifocal Atrial Tachycardia (MAT) is a supraventricular arrhythmia characterized by a heart rate >100 bpm and at least three distinct P-wave morphologies in the same lead. It is most commonly associated with underlying pulmonary diseases, particularly **COPD** or acute respiratory failure. **Why Verapamil is the correct answer:** The primary management of MAT is treating the underlying cause (e.g., correcting hypoxia or hypercapnia). However, when pharmacological rate control is required, **Calcium Channel Blockers (Verapamil or Diltiazem)** are the drugs of choice [1]. Verapamil works by slowing conduction through the AV node and suppressing the ectopic atrial foci. **Why other options are incorrect:** * **DC Shock (A):** MAT is an irregular rhythm arising from multiple foci, not a re-entrant circuit. Therefore, electrical cardioversion is ineffective and contraindicated. * **Amiodarone (B):** While it has anti-arrhythmic properties, it is not the first-line treatment for MAT and carries a higher risk of toxicity compared to CCBs [1]. * **Beta-blockers (D):** Although they can control the rate, they are generally **avoided** because MAT is frequently associated with severe COPD/Asthma, where beta-blockers can precipitate bronchospasm [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Triad:** HR >100 bpm, ≥3 different P-wave shapes, and irregular P-P intervals. * **Wandering Atrial Pacemaker (WAP):** Same ECG findings as MAT but with a heart rate <100 bpm. * **The
Question 280: All of the following are true regarding hypertrophic obstructive cardiomyopathy, except?
- A. Digitalis is useful (Correct Answer)
- B. Left ventricular outflow obstruction
- C. Asymmetrical septal thickness
- D. Double apical impulse
Explanation: **Explanation:** Hypertrophic Obstructive Cardiomyopathy (HOCM) is characterized by a dynamic pressure gradient in the subaortic region due to septal hypertrophy and systolic anterior motion (SAM) of the mitral valve. **Why Option A is the correct answer (False statement):** **Digitalis (Digoxin)** is a positive inotrope. In HOCM, increasing the force of myocardial contraction worsens the left ventricular outflow tract (LVOT) obstruction by narrowing the outflow tract further during systole. Therefore, Digitalis is **contraindicated** in HOCM (unless there is concomitant atrial fibrillation with a fast ventricular rate). Similarly, diuretics and vasodilators should be used with extreme caution as they decrease preload/afterload, which also worsens the obstruction. **Analysis of other options:** * **B. Left ventricular outflow obstruction:** This is the hallmark of HOCM, caused by the hypertrophied septum and the SAM of the mitral valve [1]. * **C. Asymmetrical septal thickness:** HOCM typically involves disproportionate thickening of the interventricular septum compared to the posterior wall (Septum:Free wall ratio > 1.3:1) [1]. * **D. Double apical impulse:** Patients often exhibit a "double" or "triple" apical impulse. The double impulse is due to a forceful atrial contraction (S4) followed by the sustained ventricular apex beat [1]. **NEET-PG High-Yield Pearls:** * **Management:** Beta-blockers are the first-line treatment (they increase diastolic filling time and decrease contractility). Calcium channel blockers (Verapamil) are also used. * **Murmur Dynamics:** The systolic murmur of HOCM **increases** with Valsalva and standing (decreased preload) and **decreases** with squatting and handgrip (increased preload/afterload). * **Jerky Pulse:** Often described as *Pulsus Bisferiens*.
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Coronary Artery Disease and Angina
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Acute Coronary Syndromes
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Heart Failure
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Cardiac Arrhythmias
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Valvular Heart Diseases
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Cardiomyopathies
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Pericardial Diseases
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Congenital Heart Disease in Adults
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Hypertension and Hypertensive Emergencies
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Pulmonary Hypertension
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Non-invasive Cardiac Diagnostics
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Preventive Cardiology
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