Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 751: Which of the following is untrue regarding sick sinus syndrome?

A. Occurs most commonly in the elderly.
B. Coronary artery disease is a common cause. (Correct Answer)
C. ECG manifestations are often intermittent.
D. Most symptomatic patients will require permanent pacing.

Explanation: Sick Sinus Syndrome (SSS) refers to a spectrum of cardiac arrhythmias caused by generalized dysfunction of the sinoatrial (SA) node. **Why Option B is the correct (untrue) statement:** While it is a common misconception, **Coronary Artery Disease (CAD) is NOT a common cause of SSS.** The most frequent underlying cause is **idiopathic degenerative fibrosis** of the SA node and the surrounding atrial myocardium [2]. Although an acute myocardial infarction (especially inferior wall MI) can cause transient SA node dysfunction, chronic CAD rarely leads to the persistent clinical syndrome of SSS. **Analysis of other options:** * **Option A:** SSS occurs most commonly in the **elderly** (typically 7th–8th decade) due to age-related fibro-degenerative changes [2]. * **Option C:** ECG manifestations are notoriously **intermittent** [1]. Patients may alternate between sinus bradycardia, sinus arrest, SA exit block, and paroxysmal supraventricular tachycardias (Tachy-Brady Syndrome) [2]. This often necessitates prolonged monitoring (Holter or ILR) for diagnosis [1]. * **Option D:** The definitive treatment for **symptomatic** SSS is the implantation of a **permanent pacemaker** (usually dual-chamber/DDDR) [1][2]. As the condition is progressive and often exacerbated by necessary rate-controlling drugs, pacing is required to alleviate symptoms like syncope or presyncope. **High-Yield Clinical Pearls for NEET-PG:** * **Tachy-Brady Syndrome:** The most common clinical presentation where periods of bradycardia are followed by paroxysmal atrial tachyarrhythmias (usually Atrial Fibrillation) [2]. * **Pharmacology:** Drugs like Beta-blockers, CCBs, and Digoxin can worsen SSS symptoms and are often the "trigger" for diagnosis. * **Intrinsic Heart Rate:** A key diagnostic feature is the failure of the heart rate to increase appropriately during exercise (Chronotropic Incompetence).

Question 752: What causes Wolff-Parkinson-White syndrome?

A. Bundle branch block
B. Right-sided accessory pathway (Correct Answer)
C. Ectopic pacemaker in the atrium
D. Left bundle branch block

Explanation: **Explanation:** **Wolff-Parkinson-White (WPW) syndrome** is a pre-excitation syndrome caused by the presence of an **accessory conduction pathway** (known as the **Bundle of Kent**) that bypasses the normal atrioventricular (AV) node [1]. This pathway directly connects the atria and the ventricles. While these pathways can be left-sided, right-sided, or septal, the presence of an accessory pathway is the fundamental anatomical defect [1], [3]. In the context of this question, a **right-sided accessory pathway** (Option B) correctly identifies the underlying mechanism of pre-excitation. **Why other options are incorrect:** * **Options A & D (Bundle Branch Blocks):** These represent delays or blocks in the normal conduction system (His-Purkinje system) below the AV node. They cause widening of the QRS complex but do not involve an accessory pathway or the characteristic "delta wave" seen in WPW. * **Option C (Ectopic pacemaker):** This refers to an abnormal site of impulse generation (like in Atrial Tachycardia). WPW is a disorder of **conduction**, not necessarily impulse generation, though it can lead to re-entrant tachycardias [2]. **High-Yield Clinical Pearls for NEET-PG:** 1. **ECG Triad:** Short PR interval (<0.12s), Delta wave (slurred upstroke of QRS), and wide QRS complex [1]. 2. **Type A vs. Type B:** Type A (Left-sided pathway) shows positive delta waves in all precordial leads (dominant R in V1). Type B (Right-sided pathway) shows negative delta waves in V1 and V2. 3. **Associated Condition:** WPW is frequently associated with **Ebstein’s Anomaly** (usually right-sided pathways). 4. **Management:** **Radiofrequency ablation** is the definitive treatment. In acute orthodromic tachycardia, use Adenosine [3]; in AF with WPW, avoid AV nodal blockers (ABCD: Adenosine, Beta-blockers, Calcium channel blockers, Digoxin) as they can precipitate ventricular fibrillation.

Question 753: Regarding Hypertrophic Obstructive Cardiomyopathy (HOCM), all are true except?

A. Myocyte disarray
B. Autosomal recessive inheritance (Correct Answer)
C. Diastolic failure
D. Bifid pulse

Explanation: Hypertrophic Obstructive Cardiomyopathy (HOCM) is a genetic cardiac disorder characterized by asymmetric septal hypertrophy and left ventricular outflow tract (LVOT) obstruction. **Why Option B is the correct answer (The "Except"):** HOCM is primarily an **Autosomal Dominant** condition with variable penetrance [1]. It is most commonly caused by mutations in genes encoding sarcomeric proteins, specifically the **Beta-myosin heavy chain** (most common) and **Myosin-binding protein C** [1]. It is not autosomal recessive. **Analysis of other options:** * **A. Myocyte disarray:** This is the hallmark histopathological feature of HOCM [1]. The normal parallel alignment of cardiac myocytes is replaced by a chaotic, "disarrayed" pattern, which serves as a substrate for ventricular arrhythmias. * **C. Diastolic failure:** In HOCM, the primary functional abnormality is **diastolic dysfunction**. The hypertrophied, stiff ventricle cannot relax properly during diastole, leading to impaired filling and increased end-diastolic pressure, despite a normal or supranormal Ejection Fraction (EF). * **D. Bifid pulse:** Also known as **Bisferiens pulse** or "spike and dome" pulse. In HOCM, there is a rapid initial contraction (spike), followed by a mid-systolic dip due to LVOT obstruction, and a second slower rise (dome). **NEET-PG High-Yield Pearls:** * **Murmur:** Harsh systolic ejection murmur heard best at the left sternal border. * **Dynamic Auscultation:** The murmur **increases** with Valsalva and standing (decreased preload) and **decreases** with squatting or handgrip (increased preload/afterload). * **ECG:** May show "dagger-like" Q waves in lateral/inferior leads. * **Drug of Choice:** Beta-blockers (first-line) or Verapamil to improve diastolic filling. **Avoid Nitrates and Diuretics** as they worsen the obstruction.

Question 754: A 60-year-old smoker presents with breathlessness for 2 weeks. On examination, heart rate is 100/min, BP = 90/60 mm Hg, and neck veins are distended with a palpable liver. CXR is shown. What is the probable diagnosis?

A. Pericardial effusion (Correct Answer)
B. Cor pulmonale
C. Broken heart syndrome
D. Brugada syndrome

Explanation: ***Pericardial effusion*** - The triad of **hypotension** (90/60 mmHg), **raised JVP** (distended neck veins), and **tachycardia** (100/min) with hepatomegaly suggests **cardiac tamponade** from pericardial effusion. - CXR likely shows the classic **"water-bottle" heart** appearance with enlarged cardiac silhouette, pathognomonic of significant pericardial effusion. *Cor pulmonale* - Results from **chronic lung disease** causing **pulmonary hypertension** and right heart failure, but would typically show signs of underlying lung pathology on CXR. - Usually presents with **elevated JVP** but **normal or elevated blood pressure**, not hypotension as seen here. *Broken heart syndrome* - **Takotsubo cardiomyopathy** typically occurs after severe **emotional or physical stress** in postmenopausal women, not fitting this demographic. - Characterized by **apical ballooning** on echocardiography and **normal coronary arteries**, with different hemodynamic profile than described. *Brugada syndrome* - A **genetic channelopathy** causing **ventricular arrhythmias** and sudden cardiac death, not heart failure symptoms. - Diagnosed by characteristic **ECG pattern** (coved ST-elevation in V1-V3) and **family history**, unrelated to the presented clinical picture.

Question 755: What is the critical degree of narrowing of coronary vessels that causes angina?

A. More than 50%
B. More than 60%
C. More than 70% (Correct Answer)
D. More than 80%

Explanation: **Explanation:** The concept of "critical stenosis" in cardiology refers to the degree of narrowing at which the coronary artery can no longer increase blood flow to meet the metabolic demands of the myocardium during exertion [1]. **Why 70% is correct:** Under resting conditions, coronary blood flow can remain normal even with significant narrowing due to compensatory distal vasodilation. However, once the luminal diameter is reduced by **more than 70%** (which corresponds to approximately an 80-90% reduction in cross-sectional area), the coronary flow reserve is exhausted. At this threshold, the vessel cannot provide the 3-to-5-fold increase in flow required during exercise, leading to subendocardial ischemia and the clinical symptom of **stable angina** [2]. **Analysis of Incorrect Options:** * **A & B (50% - 60%):** While a 50% reduction is often used to define "obstructive" coronary artery disease (CAD) on angiography, it is usually hemodynamically insignificant at rest and during moderate exercise. Most patients remain asymptomatic at this level. * **D (80%):** While 80% stenosis certainly causes angina, it is not the *minimum* threshold. The "critical" level is established at 70%. Narrowing >90% is typically required to produce symptoms even at rest (unstable angina or decubitus angina). **High-Yield Clinical Pearls for NEET-PG:** * **Stable Angina:** Occurs at >70% stenosis; pain is predictable and relieved by rest/nitroglycerin [1]. * **Rest Angina:** Usually occurs when stenosis exceeds **90%**. * **Left Main Disease:** Considered critical at **>50%** due to the massive amount of myocardium at risk. * **Fractional Flow Reserve (FFR):** A physiological measure used in the cath lab; an FFR **<0.80** indicates a lesion is hemodynamically significant, regardless of the visual percentage.

Question 756: Aggravation of symptoms of angina in a patient when given nitrates is seen in which of the following conditions?

A. Aortic regurgitation
B. Mitral regurgitation
C. Single left coronary artery stenosis
D. Idiopathic hypertrophic subaortic stenosis (Correct Answer)

Explanation: **Explanation:** The correct answer is **Idiopathic Hypertrophic Subaortic Stenosis (IHSS)**, now more commonly referred to as **Hypertrophic Obstructive Cardiomyopathy (HOCM)**. **Why HOCM is the correct answer:** In HOCM, the left ventricular outflow tract (LVOT) obstruction is dynamic. The severity of the obstruction depends on three factors: preload, afterload, and myocardial contractility. Nitrates are potent venodilators that significantly **decrease preload** (venous return) and mildly decrease afterload [1]. A reduction in ventricular volume causes the hypertrophied septum and the anterior leaflet of the mitral valve to come closer together (Systolic Anterior Motion - SAM), thereby **worsening the LVOT obstruction**. This leads to a drop in cardiac output and an increase in myocardial oxygen demand, paradoxically aggravating angina or causing syncope [1]. **Analysis of Incorrect Options:** * **Aortic Regurgitation (AR):** Nitrates (afterload reducers) are generally beneficial or neutral in AR as they reduce the backward flow of blood into the left ventricle. * **Mitral Regurgitation (MR):** Similar to AR, reducing afterload with nitrates can decrease the regurgitant fraction, often improving symptoms [2]. * **Single Left Coronary Artery Stenosis:** While nitrates must be used cautiously in severe fixed stenosis to avoid hypotension [3], they typically relieve angina by dilating collateral vessels and reducing preload/wall tension. They do not cause the dynamic worsening seen in HOCM. **Clinical Pearls for NEET-PG:** * **The "HOCM Rule":** Anything that **decreases LV volume** (Nitrates, Diuretics, Valsalva maneuver, Standing) **increases** the murmur intensity and obstruction. * **Management:** Beta-blockers or Calcium Channel Blockers (Verapamil) are first-line as they increase diastolic filling time. * **Contraindicated Drugs in HOCM:** Nitrates, Diuretics, Digitalis (increases contractility), and ACE inhibitors.

Question 757: A 49-year-old man has his serum lipids measured. Which pattern suggests the lowest risk for coronary artery disease?

A. Total cholesterol 215 mg/dL, high-density lipoprotein (HDL) cholesterol 28 mg/dL
B. Total cholesterol 215 mg/dL, HDL cholesterol 43 mg/dL
C. Total cholesterol 180 mg/dL, HDL cholesterol 29 mg/dL
D. Total cholesterol 202 mg/dL, HDL cholesterol 45 mg/dL (Correct Answer)

Explanation: The risk of coronary artery disease (CAD) is not determined by total cholesterol alone but by the balance between atherogenic lipoproteins and protective ones [1]. The most reliable predictor among the given options is the **Total Cholesterol to HDL ratio (TC/HDL ratio)** [3]. A lower ratio indicates a lower cardiovascular risk. **1. Why Option D is Correct:** In Option D, the TC/HDL ratio is **4.48** (202/45). This is the lowest ratio among all choices. Furthermore, an HDL level >40 mg/dL in men is considered protective, whereas levels <40 mg/dL are independent risk factors for CAD [2]. Option D provides the best combination of a near-optimal total cholesterol and the highest HDL level. **2. Analysis of Incorrect Options:** * **Option A:** Ratio = **7.67** (215/28). This represents the highest risk due to high total cholesterol and very low HDL (well below the 40 mg/dL threshold). * **Option B:** Ratio = **5.0** (215/43). While the HDL is acceptable, the total cholesterol is higher than in Option D, leading to a higher overall ratio. * **Option C:** Ratio = **6.20** (180/29). Despite having the lowest total cholesterol, the very low HDL (29 mg/dL) significantly increases the risk, resulting in a worse ratio than Option D. **High-Yield Clinical Pearls for NEET-PG:** * **The "Good" vs. "Bad":** HDL is anti-atherogenic (removes cholesterol from foam cells via reverse cholesterol transport), while LDL is pro-atherogenic [1]. * **Target Ratios:** A TC/HDL ratio **<3.5** is considered ideal; a ratio **>5.0** indicates high risk [3]. * **Non-HDL Cholesterol:** Calculated as (Total Cholesterol - HDL). It is often a better predictor of risk than LDL alone, especially in patients with high triglycerides. * **Negative Risk Factor:** An HDL level **≥60 mg/dL** is considered a "negative" risk factor, meaning it removes one risk factor from the total cardiovascular risk profile.

Question 758: A Carey coomb murmur is heard in which of the following conditions?

A. Constrictive pericarditis
B. Acute rheumatic carditis (Correct Answer)
C. Cardiomyopathy
D. Cardiac tamponade

Explanation: The **Carey Coombs murmur** is a classic clinical sign of **Acute Rheumatic Carditis** [1]. It is a short, mid-diastolic murmur heard best at the apex. **Why it occurs:** During the acute phase of rheumatic fever, inflammation of the endocardium (valvulitis) leads to edema and thickening of the mitral valve leaflets [3]. This creates a functional (relative) stenosis. As blood flows from the left atrium to the left ventricle during the rapid filling phase of diastole, the turbulent flow across these swollen leaflets produces the murmur. Unlike the murmur of permanent Mitral Stenosis, it is transient and disappears as the acute inflammation subsides. **Analysis of Incorrect Options:** * **A. Constrictive Pericarditis:** Characterized by a **Pericardial Knock** (an early diastolic sound) due to the sudden cessation of ventricular filling by a rigid pericardium. * **C. Cardiomyopathy:** Hypertrophic cardiomyopathy (HCM) typically presents with a harsh systolic ejection murmur [2], while Dilated Cardiomyopathy may present with a soft pansystolic murmur due to secondary Mitral Regurgitation. * **D. Cardiac Tamponade:** Classically associated with **Beck’s Triad** (hypotension, JVD, and muffled heart sounds). Murmurs are generally absent. **NEET-PG High-Yield Pearls:** * **Carey Coombs vs. Mitral Stenosis:** Carey Coombs lacks an opening snap and a loud S1, which are hallmarks of chronic rheumatic mitral stenosis [2]. * **Jones Criteria:** Carditis is a major criterion for diagnosing Acute Rheumatic Fever [1]. * **Austin Flint Murmur:** A mid-diastolic murmur heard in severe **Aortic Regurgitation** (due to the regurgitant jet displacing the mitral leaflet). * **Graham Steell Murmur:** An early diastolic murmur of **Pulmonary Regurgitation** secondary to pulmonary hypertension.

Question 759: What is not true about infective endocarditis?

A. Hematuria
B. Rose spots (Correct Answer)
C. Roth spots
D. Hemiplegia

Explanation: Infective Endocarditis (IE) is a multisystem disease characterized by infection of the endocardial surface, typically the heart valves. The clinical manifestations result from three processes: local destructive infection, septic embolization, and circulating immune complexes. **Why "Rose spots" is the correct answer:** Rose spots are small, blanching, rose-colored maculopapules found on the chest or abdomen. They are pathognomonic for **Enteric (Typhoid) Fever**, caused by *Salmonella typhi*. They are not a feature of infective endocarditis. **Analysis of incorrect options:** * **Hematuria:** This is a common finding in IE [1]. It can occur due to **embolic renal infarction** or, more characteristically, due to **immune-complex mediated glomerulonephritis** (a classic "immunological phenomenon" in Duke’s criteria). * **Roth spots:** These are retinal hemorrhages with central pale spots (white centers) caused by immune complex-mediated vasculitis [3]. They are one of the minor Duke’s criteria. * **Hemiplegia:** Neurological complications occur in up to 40% of cases [1]. Hemiplegia typically results from **septic emboli** originating from vegetations (especially from the mitral valve) leading to an ischemic stroke or a ruptured mycotic aneurysm. **High-Yield Clinical Pearls for NEET-PG:** * **Duke’s Criteria:** Remember that "Immunological phenomena" include Roth spots, Osler nodes, and Glomerulonephritis [3]. "Vascular phenomena" include Janeway lesions, Mycotic aneurysms, and Septic emboli. * **Osler Nodes vs. Janeway Lesions:** Osler nodes are **Painful** (Ouch!) and immunologic; Janeway lesions are **Painless** and embolic. * **Most common cause:** *Staphylococcus aureus* is now the most common cause of acute IE globally and in IV drug users [2]. *Viridans streptococci* remain common in subacute cases following dental procedures.

Question 760: What is true regarding cardiomyopathy?

A. RV dilatation is present
B. May result from thyroxicosis
C. Secondary to alcohol
D. All of the above (Correct Answer)

Explanation: **Explanation:** Cardiomyopathy refers to a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction. The question refers to the clinical features and etiologies of **Dilated Cardiomyopathy (DCM)**, the most common form [1]. * **Option A (RV dilatation):** In DCM, there is progressive cardiac remodeling leading to the dilatation of both the left and right ventricles [1]. While it often begins in the LV, biventricular involvement is a hallmark of advanced disease, leading to systolic dysfunction and heart failure. * **Option B (Thyrotoxicosis):** Endocrine disorders are known secondary causes of DCM. Hyperthyroidism (thyrotoxicosis) induces a hyperdynamic state that can lead to "high-output heart failure" and eventually tachycardia-induced cardiomyopathy. * **Option C (Alcohol):** Chronic alcohol consumption is one of the most common causes of secondary (acquired) DCM [1]. It exerts a direct toxic effect on the myocardium and may be exacerbated by associated nutritional deficiencies (e.g., Thiamine/B1 deficiency leading to Wet Beriberi). Since all three statements accurately describe aspects of cardiomyopathy, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of DCM:** Idiopathic (followed by genetic mutations like *TTN* encoding Titin) [1]. * **Reversibility:** Alcohol-induced cardiomyopathy and Tachycardia-induced cardiomyopathy (including thyrotoxicosis) are potentially reversible if the underlying cause is treated early. * **Diagnosis:** Echocardiography is the gold standard, showing an Ejection Fraction (EF) <40% and increased ventricular volumes. * **Peripartum Cardiomyopathy:** A specific form of DCM occurring in the last month of pregnancy or within 5 months postpartum.

Practice by Chapter

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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Cardiology — MCQs

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