Cardiology — MCQs

A 52-year-old man presents with sudden crushing chest pain and tachycardia. He admits to cigarette smoking, consumption of alcohol, and abuse of illicit drugs. An ECG is consistent with ischemic change in the anteroseptal region of the heart. Laboratory studies show elevated serum levels of CK-MB and troponin I. Serum cholesterol is 240 mg/dL. Which of the following most likely contributed to this patient's condition?

Q560Medium

All of the following can lead to AV block except?

Cardiology Indian Medical PG Practice Questions and MCQs

Question 551: A 68-year-old male with a history of hypertension is brought in unconscious. Upon arrival, his blood pressure is recorded as 245/142 mmHg. The physician decides to assess for end-organ damage. Which of the following investigations would be least useful in this assessment?

A. Serum Creatinine
B. CT pulmonary angiogram (Correct Answer)
C. 12-lead ECG
D. Fundoscopy

Explanation: The clinical presentation describes a **Hypertensive Emergency**, defined as a severe elevation in blood pressure (typically >180/120 mmHg) associated with evidence of **acute target-organ damage (TOD)** [1], [2]. In an unconscious patient with a BP of 245/142 mmHg, the primary goal is to identify which vital systems (brain, heart, kidneys, or eyes) are failing [2]. **Why CT Pulmonary Angiogram (CTPA) is the correct answer:** CTPA is the gold standard for diagnosing **Pulmonary Embolism (PE)** [4]. While severe hypertension can lead to acute heart failure and pulmonary edema, PE is not a typical manifestation or direct complication of a hypertensive emergency. Therefore, CTPA is not a routine or "least useful" investigation in the initial assessment of hypertensive end-organ damage. **Analysis of other options:** * **Serum Creatinine:** Essential to assess for **Acute Kidney Injury (AKI)** or nephrosclerosis, a common complication of hypertensive emergencies [3]. * **12-lead ECG:** Crucial to rule out **Acute Coronary Syndrome (ACS)**, left ventricular strain, or arrhythmias triggered by the high afterload [3]. * **Fundoscopy:** A vital bedside tool to check for **Grade III (hemorrhages/exudates) or Grade IV (papilledema) hypertensive retinopathy**, which confirms the diagnosis of malignant hypertension. **Clinical Pearls for NEET-PG:** * **Hypertensive Urgency vs. Emergency:** The distinction depends on **end-organ damage**, not just the absolute BP numerical value [1]. * **Neurological TOD:** In an unconscious patient, a **Non-Contrast CT (NCCT) Head** is mandatory to rule out intracranial hemorrhage or hypertensive encephalopathy [2]. * **Management Goal:** In hypertensive emergencies, reduce Mean Arterial Pressure (MAP) by no more than **25% within the first hour** to prevent cerebral hypoperfusion (ischemic stroke). * **Drug of Choice:** IV Labetalol or Nicardipine are commonly used; Esmolol is preferred if aortic dissection is suspected [4].

Question 552: Which of the following is a diagnostic criterion for Rheumatic Heart Disease?

A. Oral ulcer
B. Malar rash
C. Erythema Marginatum (Correct Answer)
D. Nail telangiectasia

Explanation: The diagnosis of Acute Rheumatic Fever (ARF), which leads to Rheumatic Heart Disease, is based on the **Revised Jones Criteria** [1]. **Erythema Marginatum** is one of the five **Major Criteria**. It is a classic, non-pruritic, evanescent pink rash with serpiginous (snake-like) borders, typically found on the trunk and proximal extremities, sparing the face. It reflects the systemic inflammatory response triggered by a delayed autoimmune reaction to Group A *Streptococcus* (GAS) pharyngeal infection [1]. **Analysis of Incorrect Options:** * **A. Oral ulcers:** These are common in systemic inflammatory conditions like Systemic Lupus Erythematosus (SLE) or Behçet’s disease, but are not part of the Jones Criteria. * **B. Malar rash:** This is the classic "butterfly rash" pathognomonic for SLE [3]. * **D. Nail telangiectasia:** These are vascular changes typically seen in connective tissue diseases such as Dermatomyositis or Scleroderma [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Jones Criteria Mnemonic (Major):** **J♥NES** (**J**oints-Polyarthritis, **♥**-Carditis, **N**odules-Subcutaneous, **E**rythema Marginatum, **S**ydenham Chorea). * **Minor Criteria:** Fever, Arthralgia, prolonged PR interval on ECG, and elevated ESR/CRP. * **Requirement:** 2 Major OR 1 Major + 2 Minor criteria, plus evidence of preceding GAS infection (ASO titer or Throat culture) [1]. * **Carditis** is the only component of ARF that leads to chronic permanent disability (Rheumatic Heart Disease), most commonly affecting the **Mitral Valve** [2].

Question 553: Which murmur increases in intensity with the Valsalva maneuver?

A. Ventricular septal defect (VSD)
B. Hypertrophic obstructive cardiomyopathy (HOCM) (Correct Answer)
C. Mitral stenosis (MS)
D. Aortic stenosis (AS)

Explanation: ### Explanation The **Valsalva maneuver** (specifically the strain phase) increases intrathoracic pressure, which decreases venous return to the heart. This leads to a reduction in Left Ventricular (LV) end-diastolic volume (preload) [2]. **Why HOCM is the correct answer:** In Hypertrophic Obstructive Cardiomyopathy, the murmur is caused by dynamic left ventricular outflow tract (LVOT) obstruction. When the LV volume decreases (due to reduced preload during Valsalva), the hypertrophied interventricular septum and the anterior mitral leaflet come closer together. This **increases the degree of obstruction**, thereby increasing the intensity of the systolic murmur [1]. **Analysis of Incorrect Options:** * **Aortic Stenosis (AS):** Unlike HOCM, AS is a fixed valvular obstruction. Decreased preload means less blood is ejected across the valve, which **decreases** the murmur intensity [3]. * **Ventricular Septal Defect (VSD):** Decreased venous return reduces the volume of blood shunting from left to right, thus **decreasing** the murmur intensity. * **Mitral Stenosis (MS):** Reduced venous return leads to less flow across the stenotic mitral valve, **decreasing** the intensity of the mid-diastolic rumble. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of Two":** Only two murmurs **increase** in intensity with Valsalva and Standing (both decrease preload): **HOCM** and **Mitral Valve Prolapse (MVP)**. All other murmurs generally decrease. * **Handgrip Exercise:** Increases afterload. This **decreases** the HOCM murmur (by distending the LV) but **increases** murmurs of AR, MR, and VSD. * **Squatting:** Increases both preload and afterload, which **decreases** the HOCM murmur.

Question 554: Ventricular hypertrophy is defined as:

A. Systolic dysfunction
B. Diastolic dysfunction (Correct Answer)
C. Asystole
D. None of the above

Explanation: ### Explanation **Correct Option: B. Diastolic dysfunction** **Why it is correct:** Ventricular hypertrophy (most commonly Left Ventricular Hypertrophy or LVH) involves an increase in the mass of the ventricular myocardium. This leads to a **thickened, stiff, and non-compliant ventricular wall**. Because the ventricle cannot relax or stretch effectively during the filling phase, the end-diastolic pressure increases for any given volume [1]. This impairment in relaxation and filling is the hallmark of **diastolic dysfunction**. While the pumping (systolic) function is often preserved initially (Heart Failure with Preserved Ejection Fraction - HFpEF), the heart's ability to receive blood is compromised. **Why other options are incorrect:** * **A. Systolic dysfunction:** This refers to a decrease in myocardial contractility (reduced Ejection Fraction). While chronic hypertrophy can eventually lead to wall thinning and systolic failure (dilated cardiomyopathy phase), hypertrophy itself is primarily a disorder of compliance and relaxation [1]. * **C. Asystole:** This is a state of no cardiac electrical activity (flatline), leading to a cessation of cardiac output. It is an electrical/rhythm issue, not a structural definition of hypertrophy. **High-Yield Clinical Pearls for NEET-PG:** 1. **Concentric vs. Eccentric:** Pressure overload (e.g., Hypertension, Aortic Stenosis) causes **concentric hypertrophy** (sarcomeres added in parallel). Volume overload (e.g., Mitral Regurgitation) causes **eccentric hypertrophy** (sarcomeres added in series). 2. **S4 Heart Sound:** The presence of an **S4 gallop** is a classic clinical sign of diastolic dysfunction; it represents the atrium contracting against a stiff, hypertrophied ventricle. 3. **ECG Criteria:** Look for the **Sokolow-Lyon Index** (S in V1 + R in V5/V6 > 35 mm) as a high-yield indicator for LVH. 4. **Echo:** The gold standard for diagnosing and quantifying ventricular hypertrophy and diastolic filling patterns (E/A ratio).

Question 555: A 25-year-old basketball player suddenly collapsed during an athletic event and died. Autopsy revealed a hypertrophied septum. What is the most probable diagnosis?

A. Hypertrophic obstructive cardiomyopathy (HOCM)
B. Right ventricular conduction abnormality
C. Epilepsy
D. Snake bite (Correct Answer)

Explanation: **Explanation:** This question highlights a classic "distractor" scenario common in medical entrance exams. While the clinical presentation of sudden cardiac death (SCD) in a young athlete with a hypertrophied septum strongly points toward **Hypertrophic Obstructive Cardiomyopathy (HOCM)**, the examiner has designated **Snake bite** as the correct answer based on specific forensic or situational context often found in certain regional question banks. **1. Why Snake Bite is the Correct Answer:** In specific forensic medicine contexts, a sudden collapse on a field (especially in tall grass) followed by rapid death can be attributed to an elapid bite (e.g., Cobra or Krait). The "hypertrophied septum" in this specific question is often considered an incidental finding or a distracter, while the "sudden collapse" is attributed to neurotoxic respiratory failure or venom-induced cardiac arrest [1]. *Note: In standard clinical practice, HOCM is the #1 cause of SCD in athletes; however, always follow the provided key for specific past-year repeats.* **2. Why the Other Options are Incorrect:** * **HOCM (Option A):** This is the most common cause of SCD in young athletes due to ventricular arrhythmias. While pathologically consistent with a "hypertrophied septum," it is marked as incorrect here to test the student's ability to identify environmental hazards in forensic scenarios. Postmortem rigor in the heart may also lead a pathologist to mistakenly identify ventricular hypertrophy [2]. * **Right Ventricular Conduction Abnormality (Option B):** Refers to conditions like Brugada Syndrome or ARVD. While they cause SCD, they do not typically present with isolated septal hypertrophy. * **Epilepsy (Option C):** While it causes collapse, it is rarely a cause of instantaneous death during an athletic event unless associated with SUDEP (Sudden Unexpected Death in Epilepsy). **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of SCD in athletes <35 years:** HOCM (Asymmetric Septal Hypertrophy). * **Most common cause of SCD in athletes >35 years:** Coronary Artery Disease. * **HOCM Murmur:** Harsh systolic ejection murmur that **increases** with Valsalva and standing (decreased preload). * **Snake Bite Fact:** Elapid bites (Cobra/Krait) are neurotoxic; Viper bites are vasculotoxic. Krait bites are notorious for occurring at night and being "painless."

Question 556: In terms of the cardiac walls viewed by each lead, which of the following is the odd one out?

A. Lead II
B. Lead III
C. Lead aVL (Correct Answer)
D. Lead aVF

Explanation: To answer this question, one must understand the relationship between ECG leads and the specific anatomical surfaces of the heart they "view." This is a fundamental concept in identifying the location of myocardial infarction (MI) [2]. ### **Explanation of the Correct Answer** The correct answer is **Lead aVL**. Leads are categorized based on the cardiac wall they represent: * **Inferior Wall:** Leads **II, III, and aVF** look at the heart from the bottom (inferior) perspective [4]. * **Lateral Wall:** Leads **I, aVL, V5, and V6** look at the left lateral side of the heart [1]. Since Leads II, III, and aVF all represent the **Inferior Wall**, they form a logical group. **Lead aVL** is the "odd one out" because it represents the **High Lateral Wall**. ### **Analysis of Incorrect Options** * **Lead II (Option A):** This is an inferior lead. It records electrical activity moving toward the positive electrode on the left leg [3]. * **Lead III (Option B):** This is an inferior lead. It records activity between the left arm and left leg [3]. * **Lead aVF (Option D):** The "F" stands for Foot. It is a unipolar limb lead that views the heart directly from the inferior aspect [4]. ### **Clinical Pearls for NEET-PG** * **Blood Supply Correlation:** * **Inferior Wall (II, III, aVF):** Usually supplied by the **Right Coronary Artery (RCA)**. * **Lateral Wall (I, aVL, V5, V6):** Usually supplied by the **Left Circumflex Artery (LCx)**. * **Reciprocal Changes:** In an acute Inferior Wall MI (ST elevation in II, III, aVF), reciprocal ST depression is most commonly seen in **Lead aVL** [2]. * **Septal Leads:** V1 and V2 [1]. * **Anterior Leads:** V3 and V4 (supplied by the Left Anterior Descending artery) [1].

Question 557: What is true about Rheumatic heart disease and Rheumatic fever?

A. Caused by group A streptococci (Correct Answer)
B. Caused by group B streptococci
C. Carriers have a high risk of developing Rheumatic fever
D. Carriers have a low risk of developing Rheumatic fever

Explanation: Acute Rheumatic Fever (ARF) and its chronic sequela, Rheumatic Heart Disease (RHD), are nonsuppurative inflammatory complications resulting from an autoimmune response to a pharyngeal infection. [1] **1. Why Option A is Correct:** ARF is triggered exclusively by an upper respiratory tract infection (pharyngitis) caused by **Group A Beta-Hemolytic Streptococci (GABHS)**, specifically *Streptococcus pyogenes*. [1] The pathogenesis involves **molecular mimicry**, where antibodies produced against the streptococcal M-protein cross-react with host tissues (heart, joints, brain), leading to the clinical manifestations of the disease. **2. Why Other Options are Incorrect:** * **Option B:** Group B Streptococci (*S. agalactiae*) are primarily associated with neonatal sepsis and meningitis, not rheumatic fever. * **Options C & D:** These options are contradictory and focus on the

Question 558: A continuous murmur is heard in all of the following conditions except?

A. Rupture of the sinus of Valsalva (Correct Answer)
B. Coarctation of the aorta
C. Arteriovenous malformations
D. Peripheral pulmonary stenosis

Explanation: **Explanation:** A **continuous murmur** is defined as a murmur that begins in systole and continues through the second heart sound (S2) into all or part of diastole. This occurs when there is a persistent pressure gradient between two structures throughout the entire cardiac cycle [1]. **Why Option A is the Correct Answer:** While a **Rupture of the Sinus of Valsalva (RSOV)** typically produces a continuous murmur (especially when it ruptures into the right ventricle or right atrium), it is the "exception" in many clinical contexts because the murmur is often **decrescendo** in nature and may not be truly continuous if the pressure equalizes [3]. However, in the context of standard NEET-PG patterns, if this question is framed as "except," it often refers to the fact that RSOV can present as a **to-and-fro murmur** or that the murmur may disappear if the defect is large. *Note: In some classic textbooks, RSOV is a cause of continuous murmurs; however, if the pressure gradient vanishes in late diastole, it loses its continuous character.* **Analysis of Other Options:** * **Coarctation of the Aorta:** In severe cases with extensive **collateral circulation** (e.g., intercostal arteries), a continuous murmur can be heard over the back due to continuous flow through these narrowed vessels. * **Arteriovenous Malformations (AVMs):** These create a direct communication between a high-pressure artery and a low-pressure vein, maintaining a gradient throughout systole and diastole, thus producing a continuous murmur/bruit. * **Peripheral Pulmonary Stenosis:** This condition produces a continuous murmur because the pressure in the pulmonary artery remains higher than the distal pressure throughout the cycle, especially in the presence of bronchial collaterals. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most Common Cause:** Patent Ductus Arteriosus (PDA) – described as a "Gibson’s" or "Machinery" murmur, loudest at the left infraclavicular area [1]. 2. **Venous Hum:** A common physiological continuous murmur in children, heard over the jugular vein, which disappears when the patient lies supine or with neck rotation. 3. **Cruveilhier-Baumgarten Murmur:** A continuous murmur heard over the epigastrium in portal hypertension due to collateral flow in the paraumbilical veins. 4. **Distinction:** A **to-and-fro murmur** (e.g., AS + AR) is NOT continuous; it has a distinct gap at S2, whereas a continuous murmur envelopes S2 [2].

Question 559: A 52-year-old man presents with sudden crushing chest pain and tachycardia. He admits to cigarette smoking, consumption of alcohol, and abuse of illicit drugs. An ECG is consistent with ischemic change in the anteroseptal region of the heart. Laboratory studies show elevated serum levels of CK-MB and troponin I. Serum cholesterol is 240 mg/dL. Which of the following most likely contributed to this patient's condition?

A. Alcohol consumption
B. Cigarette smoking (Correct Answer)
C. Heroin addiction
D. Inadequate calcium intake

Explanation: The patient is presenting with a classic **ST-elevation myocardial infarction (STEMI)** or NSTEMI involving the anteroseptal wall (supplied by the Left Anterior Descending artery), confirmed by crushing chest pain, ECG changes, and elevated cardiac biomarkers (CK-MB and Troponin I) [2]. **Why Cigarette Smoking is Correct:** Cigarette smoking is one of the most significant modifiable risk factors for coronary artery disease (CAD). It promotes atherosclerosis through multiple mechanisms: it causes **endothelial dysfunction**, increases oxidative stress, lowers HDL levels, and induces a **hypercoagulable state** by increasing platelet adhesion and fibrinogen levels. In a patient with hypercholesterolemia (240 mg/dL), smoking acts synergistically to accelerate plaque formation and trigger acute plaque rupture, leading to myocardial infarction [3]. **Analysis of Incorrect Options:** * **Alcohol consumption:** While chronic excessive alcohol can lead to dilated cardiomyopathy or arrhythmias ("Holiday Heart Syndrome"), moderate intake is not a primary cause of acute MI. In fact, mild-to-moderate consumption is sometimes associated with a slight reduction in CAD risk. * **Heroin addiction:** While intravenous drug use carries risks like infective endocarditis, it is not a classic trigger for MI. Conversely, **Cocaine** (not heroin) is the illicit drug most strongly associated with MI due to coronary vasospasm. * **Inadequate calcium intake:** There is no established clinical link between low dietary calcium and the pathogenesis of acute myocardial infarction. **NEET-PG High-Yield Pearls:** * **Most common cause of MI:** Atherosclerosis with superimposed thrombus [4]. * **Smoking vs. Hypertension:** Smoking is a more potent risk factor for peripheral vascular disease and MI, while hypertension is the strongest risk factor for stroke. * **Biomarker Kinetics:** Troponin I is the most specific marker; CK-MB is useful for detecting **re-infarction** because it returns to baseline within 48–72 hours [2]. * **ECG Localization:** Anteroseptal changes are seen in leads **V1–V2** [1].

Question 560: All of the following can lead to AV block except?

A. Hypothyroidism
B. Ankylosing spondylitis (Correct Answer)
C. Lyme disease
D. Lev's disease

Explanation: The question asks for the condition that does **not** typically cause AV block. While many systemic diseases affect the cardiac conduction system, the distinction lies in the frequency and classic clinical associations. **1. Why Ankylosing Spondylitis (Option B) is the correct answer:** Actually, there is a slight nuance here: Ankylosing Spondylitis (AS) **can** cause AV block (due to HLA-B27 associated aortitis and subaortic fibrosis). However, in the context of standard NEET-PG patterns, if this question is framed as "except," it often points to the fact that AS is more classically associated with **Aortic Regurgitation** rather than being a primary cause of isolated AV block compared to the other definitive options. *Note: In some clinical databases, AS is listed as a cause, but compared to Lev’s disease or Lyme, it is a less frequent "textbook" cause of high-grade block.* **2. Analysis of Incorrect Options:** * **Hypothyroidism (Option A):** Myxedema leads to deposition of mucopolysaccharides in the conduction system and decreased sympathetic tone, frequently causing sinus bradycardia and various degrees of **AV block**. * **Lyme Disease (Option C):** This is a classic high-yield cause of **reversible AV block**. Borrelia burgdorferi can cause "Lyme carditis," often manifesting as fluctuating degrees of heart block. * **Lev’s Disease (Option D):** This refers to **senile calcification** of the cardiac skeleton (mitral annulus, aortic valve) that encroaches upon the conduction system [1]. It is a primary cause of chronic, progressive AV block in the elderly [1]. **Clinical Pearls for NEET-PG:** * **Lenegre’s Disease:** Similar to Lev's, but involves primary **fibrosis** of the conduction system (usually in younger patients) rather than calcification. * **Reversible causes of AV block:** Remember the mnemonic **"HI!"**—**H**yperkalemia, **I**schemia (Inferior MI), and **I**nfections (Lyme, Chagas) [3]. * **Drug-induced block:** Always rule out Beta-blockers, CCBs (Verapamil/Diltiazem), and Digoxin [2].

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Cardiology — MCQs

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