Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 811: All of the following are features of the Mohs' triad in pericardial effusion, except?

A. Widening of the cardiac silhouette
B. Bunting of the cardiophrenic angle on the right side (Correct Answer)
C. An increase in cardiac dullness in the second intercostal space
D. An abrupt transition of pulmonary resonance to cardiac dullness

Explanation: ### Explanation **Mohs' Triad** is a classic clinical and radiological sign used to identify significant pericardial effusion. It focuses on the physical examination and radiographic changes that occur as fluid accumulates in the pericardial sac. **Why Option B is the Correct Answer:** The correct feature is actually the **obliteration or "blunting" of the cardiophrenic angle on the left side**, not the right. In pericardial effusion, fluid tends to accumulate in the most dependent parts of the pericardium. On a chest X-ray, this manifests as the loss of the sharp angle between the heart and the diaphragm, typically starting on the left. Therefore, "blunting on the right side" is the incorrect statement. **Analysis of Incorrect Options:** * **Option A (Widening of the cardiac silhouette):** This is a hallmark of pericardial effusion [1]. As fluid volume increases (usually >250ml), the heart shadow expands symmetrically, leading to the classic "water-bottle" or "money-bag" appearance [1]. * **Option C (Increase in cardiac dullness in the 2nd ICS):** Normally, the 2nd intercostal space is resonant. In large effusions, fluid fills the superior recesses of the pericardium, extending the area of dullness upward. * **Option D (Abrupt transition of resonance to dullness):** On percussion, there is a sharp, sudden change from the resonant lung sound to absolute cardiac dullness, rather than the gradual transition seen in cardiomegaly. **NEET-PG High-Yield Pearls:** * **Ewart’s Sign:** Dullness and bronchial breathing at the left infrascapular area due to compression of the left lung base by the large pericardial sac. * **Beck’s Triad (Cardiac Tamponade):** Hypotension, JVD, and muffled heart sounds. * **Electrical Alternans:** A pathognomonic ECG finding in large effusions due to the "swinging heart" motion [1]. * **Gold Standard Investigation:** Echocardiography is the most sensitive and specific test for diagnosing pericardial effusion [1].

Question 812: Diagnosis of tubercular pericarditis can be done by:

A. Chest X-ray
B. USG
C. MRI
D. Aspiration and culture (Correct Answer)

Explanation: **Explanation:** **Tubercular Pericarditis** is a common cause of chronic pericardial effusion and constrictive pericarditis in endemic regions like India. **Why Aspiration and Culture is the correct answer:** The definitive diagnosis of tubercular pericarditis requires the demonstration of *Mycobacterium tuberculosis* in the pericardial fluid or biopsy of the pericardium [2]. 1. **Pericardiocentesis (Aspiration):** The fluid is typically an exudate with high protein and high adenosine deaminase (ADA) levels (>40 U/L). The diagnosis may be confirmed by aspiration of the fluid and direct examination or culture for tubercle bacilli [2]. 2. **Culture:** While direct microscopy (AFB staining) has low sensitivity (40-60%), **culture** (using MGIT or LJ medium) remains the gold standard for confirming the presence of the bacilli and determining drug sensitivity. **Why other options are incorrect:** * **Chest X-ray (A):** It may show cardiomegaly (water-bottle heart) or calcification in chronic cases, but these findings are non-specific and cannot differentiate TB from other causes of effusion. * **USG/Echocardiography (B):** This is the most sensitive tool to *detect* fluid and guide aspiration, but it cannot provide an etiological diagnosis. * **MRI (C):** Useful for assessing pericardial thickening and inflammation in constrictive pericarditis, but it lacks the specificity to diagnose tuberculosis. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Pericardial biopsy (showing granulomas) combined with fluid culture [1]. * **Biochemical Marker:** **ADA (Adenosine Deaminase)** levels >40 U/L in pericardial fluid are highly suggestive of TB. * **Treatment:** Standard ATT for 6 months. The use of **adjunctive corticosteroids** is recommended to reduce the risk of progression to constrictive pericarditis [1], [2]. * **Commonest Complication:** Chronic constrictive pericarditis [2].

Question 813: Infective endocarditis is commonly seen in all the following conditions except?

A. Small VSD
B. Tetralogy of Fallot
C. PDA
D. ASD (Correct Answer)

Explanation: The risk of **Infective Endocarditis (IE)** is primarily determined by the degree of **turbulence** in blood flow and the resulting pressure gradient across a cardiac defect. High-velocity jets cause endothelial damage, leading to the deposition of fibrin and platelets (non-bacterial thrombotic endocarditis), which serves as a nidus for bacterial colonization [1]. **Why ASD is the correct answer:** In a Secundum **Atrial Septal Defect (ASD)**, the pressure gradient between the left and right atria is very low. This results in low-velocity, non-turbulent flow across the defect. Consequently, the endocardium is not predisposed to the shear stress required to initiate the pathogenesis of IE. Therefore, ASD is considered a **low-risk** condition for IE. **Why the other options are incorrect:** * **Small VSD (Option A):** Small Ventricular Septal Defects (Maladie de Roger) create high-velocity systolic jets due to the large pressure gradient between the left and right ventricles, making them **high-risk** for IE. * **Tetralogy of Fallot (Option B):** TOF involves high-velocity flow across the VSD and turbulent flow through the right ventricular outflow tract (pulmonary stenosis), placing it in the **high-risk** category. * **PDA (Option C):** Patent Ductus Arteriosus involves a continuous high-pressure gradient from the aorta to the pulmonary artery, creating significant turbulence and a **high risk** for IE. **High-Yield Clinical Pearls for NEET-PG:** * **Highest Risk Conditions:** Prosthetic heart valves, previous IE, Cyanotic congenital heart disease (unrepaired), and Coarctation of the aorta. * **Low-Risk Conditions:** Secundum ASD, Ischemic heart disease, and Mitral Valve Prolapse *without* regurgitation. * **Commonest Valve Involved:** Mitral valve (overall); Tricuspid valve (in IV drug users). * **Commonest Organism:** *Staphylococcus aureus* (Acute IE/IVDU); *Viridans streptococci* (Subacute IE).

Question 814: Which of the following is a cause of 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 into the left ventricle from the aorta during diastole [3]. This leads to: 1. **Increased SBP:** The left ventricle handles an increased stroke volume (normal venous return + regurgitant volume), leading to a forceful contraction [1]. 2. **Decreased DBP:** The rapid "runoff" of blood back into the ventricle and into the periphery causes a significant drop in diastolic pressure [3]. The combination of high SBP and low DBP results in a classic wide pulse pressure. **Analysis of Incorrect Options:** * **Aortic Stenosis (AS):** Characterized by a **narrow pulse pressure** (*pulsus parvus et tardus*). The obstructed outflow reduces stroke volume and SBP [2]. * **Mitral Stenosis (MS):** Leads to reduced left ventricular filling, which decreases stroke volume and results in a narrow pulse pressure [4]. * **Tricuspid Stenosis (TS):** Reduces right-sided cardiac output, ultimately leading to decreased left-sided filling and a narrow pulse pressure [4]. **High-Yield Clinical Pearls for NEET-PG:** * **Water-Hammer Pulse (Corrigan’s Pulse):** A rapid, forceful upstroke and sudden collapse of the pulse, characteristic of AR [1]. * **Other causes of Wide Pulse Pressure:** Thyrotoxicosis, Anemia, Patent Ductus Arteriosus (PDA), Beriberi, and Atherosclerosis (due to stiffened arteries). * **Traube’s Sign:** "Pistol shot" sounds heard over the femoral arteries in AR. * **Duroziez's Sign:** A systolic and diastolic murmur heard over the femoral artery when compressed.

Question 815: What is the most common cause of hypertension in a 45-year-old male with a 20-year history of smoking?

A. Atherosclerosis (Correct Answer)
B. Fibromuscular dysplasia
C. Neurofibromatosis type 1
D. Aortic dissection

Explanation: **Explanation:** The correct answer is **Atherosclerosis**. **1. Why Atherosclerosis is Correct:** In a 45-year-old male with a significant smoking history, the most likely cause of secondary hypertension (specifically renovascular hypertension) is **Atherosclerotic Renal Artery Stenosis (ARAS)**. Atherosclerosis typically affects the **proximal third (ostium)** of the renal artery. Smoking is a major independent risk factor that accelerates plaque formation [2]. The resulting decrease in renal perfusion activates the Renin-Angiotensin-Aldosterone System (RAAS), leading to systemic hypertension [2]. **2. Why the Other Options are Incorrect:** * **B. Fibromuscular Dysplasia (FMD):** While FMD is a common cause of renovascular hypertension, it typically affects **young females (20–40 years)** and involves the distal two-thirds of the renal artery ("string of beads" appearance). It is less likely in an older male smoker. * **C. Neurofibromatosis type 1 (NF1):** NF1 is associated with hypertension due to pheochromocytoma or renal artery stenosis, but it is a rare genetic condition and not the "most common" cause in this demographic. * **D. Aortic Dissection:** This is a life-threatening *complication* or consequence of long-standing hypertension, rather than a primary cause of it [2]. **3. NEET-PG High-Yield Pearls:** * **Renovascular Hypertension:** The most common cause of secondary hypertension overall [1]. * **Age/Gender Split:** If the patient is a young female, think **FMD**; if the patient is an older male smoker, think **Atherosclerosis**. * **Clinical Clue:** Presence of an abdominal bruit or a sudden rise in serum creatinine (>30%) after starting an ACE inhibitor/ARB is highly suggestive of renal artery stenosis. * **Gold Standard Investigation:** Renal Angiography. * **Screening Investigation:** Doppler Ultrasound or CT/MR Angiography.

Question 816: Total electrical alternans in ECG along with sinus tachycardia is a specific sign of which condition?

A. Left ventricular failure
B. Cardiac tamponade (Correct Answer)
C. Wet beriberi
D. Hypertrophic cardiomyopathy

Explanation: **Explanation:** **Total Electrical Alternans** refers to the beat-to-beat variation in the amplitude and axis of all ECG waveforms (P waves, QRS complexes, and T waves). When combined with **sinus tachycardia**, it is a highly specific sign of **Cardiac Tamponade** [1]. 1. **Why Cardiac Tamponade is correct:** In large pericardial effusions, the heart is not fixed in place; it literally "swings" back and forth within the fluid-filled pericardial sac [1]. This physical movement changes the heart's electrical axis relative to the ECG electrodes with every beat. Sinus tachycardia occurs as a compensatory mechanism to maintain cardiac output in the face of restricted ventricular filling. 2. **Why other options are incorrect:** * **Left Ventricular Failure:** May show signs of left ventricular hypertrophy (LVH) or left bundle branch block (LBBB), but not total electrical alternans. * **Wet Beriberi:** Characterized by high-output heart failure, peripheral vasodilation, and edema. ECG usually shows non-specific ST-T changes or tachycardia, but not the "swinging heart" phenomenon. * **Hypertrophic Cardiomyopathy (HCM):** Typically presents with features of LVH, deep "dagger-like" Q waves (lateral leads), and T-wave inversions. **High-Yield Clinical Pearls for NEET-PG:** * **Beck’s Triad:** Hypotension, Jugular Venous Distension (JVD), and Muffled heart sounds (classic for acute tamponade). * **Pulsus Paradoxus:** An inspiratory drop in systolic BP >10 mmHg; a hallmark clinical finding. * **ECG Hierarchy:** While **low voltage QRS** is the most common ECG finding in tamponade, **total electrical alternans** is the most specific [1]. * **Management:** Immediate **pericardiocentesis** is the treatment of choice [1].

Question 817: An 18-year-old male presents with loss of consciousness. He regained consciousness in the ER, with a GCS of 12/15 on admission. His neurological examination is normal. On auscultation, a narrow split S2 and clear lungs are noted. An ECG was performed. What is the most likely diagnosis?

A. Left outflow tract obstruction (Correct Answer)
B. Right outflow tract obstruction
C. Atrial fibrillation with cerebral embolism
D. Subarachnoid hemorrhage with T wave inversion

Explanation: ***Left outflow tract obstruction*** - **Syncope** in a young male with **narrow split S2** is highly suggestive of **hypertrophic cardiomyopathy (HCM)** causing left ventricular outflow tract (LVOT) obstruction. - ECG typically shows **left ventricular hypertrophy** and **dagger Q waves** in lateral leads, which are pathognomonic for HCM in young patients. *Right outflow tract obstruction* - Would cause **wide split S2** due to delayed pulmonic valve closure, not the narrow split S2 observed. - Conditions like **pulmonary stenosis** or **tetralogy of Fallot** typically present with **cyanosis** and **murmurs**, which are absent here. *Atrial fibrillation with cerebral embolism* - Would show **irregular rhythm** on ECG and often presents with **focal neurological deficits**, not loss of consciousness with normal neurological examination. - **Embolic stroke** typically causes persistent neurological symptoms, not transient loss of consciousness with complete recovery. *Subarachnoid hemorrhage with T wave inversion* - Would present with **severe headache**, **neck stiffness**, and **photophobia**, which are not described in this case. - **Neurological examination** would typically show signs of **meningeal irritation** or **focal deficits**, not a normal examination as described.

Question 818: Which of the following is NOT a feature of acute pericarditis?

A. Concave ST elevation
B. PR segment depression (Correct Answer)
C. J point elevation
D. Reciprocal ST depression

Explanation: ### Explanation The question asks for the feature that is **NOT** a characteristic of acute pericarditis. However, there is a technical nuance in the options provided: **PR segment depression** is actually a classic, diagnostic hallmark of acute pericarditis. In the context of standard NEET-PG patterns, if the "correct" answer is marked as PR depression, it implies the question is likely asking for the feature that is **pathognomonic** or most specific, or there is a clerical error in the question's "NOT" phrasing. However, strictly evaluating the features of Acute Pericarditis: 1. **PR segment depression (Option B):** This is a **classic feature** of Stage 1 acute pericarditis [1]. It occurs due to subepicardial atrial injury. It is seen in all leads except aVR (where PR elevation occurs). 2. **Concave ST elevation (Option A):** This is the most common ECG finding [1]. Unlike the convex (tombstone) ST elevation seen in MI, pericarditis presents with diffuse, concave-upwards ST elevation [1]. 3. **J point elevation (Option C):** The ST elevation in pericarditis starts at the J point. This is a common finding in both pericarditis and benign early repolarization. 4. **Reciprocal ST depression (Option D):** In acute pericarditis, ST elevation is **diffuse**. Therefore, reciprocal ST depression is **absent** (except in leads aVR and V1). If you see prominent reciprocal changes in other leads, it strongly suggests an Acute Myocardial Infarction rather than pericarditis. **High-Yield NEET-PG Pearls:** * **Stage 1 ECG:** Diffuse concave ST elevation + PR depression (Most specific) [1]. * **Spodick’s Sign:** Downsloping of the TP segment (seen in ~80% of cases). * **Clinical Triad:** Pleuritic chest pain (relieved by sitting forward), Pericardial friction rub, and diffuse ECG changes. * **Treatment:** NSAIDs + Colchicine (to prevent recurrence) [1]. Steroids are second-line [1].

Question 819: A 22-year-old woman complains of palpitations and has a regular heartbeat at a rate of 170/min, with a blood pressure of 110/70 mm Hg. The rate abruptly changes to 75/min after applying carotid sinus pressure. Which of the following is the most likely diagnosis?

A. sinus tachycardia
B. paroxysmal atrial fibrillation
C. paroxysmal atrial flutter
D. paroxysmal supraventricular tachycardia (PSVT) (Correct Answer)

Explanation: ### Explanation **1. Why PSVT is the Correct Answer** The clinical presentation is classic for **Paroxysmal Supraventricular Tachycardia (PSVT)**, most commonly AV Nodal Reentrant Tachycardia (AVNRT). [1] * **Rate and Rhythm:** PSVT typically presents with a regular, narrow-complex tachycardia at rates between 150–250 bpm. [1] * **Response to Vagal Maneuvers:** The hallmark of PSVT is its **abrupt** onset and termination. [3] Carotid sinus pressure (a vagal maneuver) increases parasympathetic tone to the AV node, which can suddenly break the re-entrant circuit and restore normal sinus rhythm (75/min in this case). [2] **2. Why Other Options are Incorrect** * **Sinus Tachycardia:** This is a physiological response. Vagal maneuvers cause only a **gradual slowing** of the heart rate, which returns to the original fast rate once the maneuver stops. It does not terminate abruptly. * **Atrial Fibrillation (AF):** AF is characterized by an **irregularly irregular** rhythm. [3] Carotid sinus pressure might slow the ventricular rate temporarily but will not convert AF to sinus rhythm. * **Atrial Flutter:** This typically presents with a "sawtooth" pattern and a fixed conduction ratio (e.g., 2:1). Vagal maneuvers increase the AV block (e.g., moving from 2:1 to 4:1), making the flutter waves more visible, but they **do not terminate** the underlying atrial flutter. **3. NEET-PG High-Yield Pearls** * **Drug of Choice:** For acute management of stable PSVT, **Adenosine** (6mg IV rapid bolus) is the first-line pharmacological treatment. * **Definitive Treatment:** **Radiofrequency Ablation (RFA)** of the slow pathway is the treatment of choice for recurrent episodes. * **ECG Finding:** Look for "pseudo-R prime" in lead V1 or "pseudo-S waves" in inferior leads, representing retrograde P-waves.

Question 820: Which of the following differentiates ventricular tachycardia from Wolff-Parkinson-White (WPW) pattern with atrial fibrillation?

A. Irregular RR interval
B. Regular RR interval (Correct Answer)
C. Broad QRS
D. Increased heart rate

Explanation: This question tests the ability to differentiate between two life-threatening wide-complex tachycardias (WCT). The key to distinguishing them lies in the **regularity of the rhythm**. [1] ### **Explanation of the Correct Answer** * **Ventricular Tachycardia (VT):** This rhythm originates from a single ectopic focus or re-entry circuit within the ventricles. Consequently, the electrical impulses are discharged at a constant rate, leading to a **regular RR interval**. [1] * **WPW with Atrial Fibrillation (Pre-excited AF):** In this condition, the underlying rhythm is AF (which is "irregularly irregular"). These chaotic atrial impulses are conducted to the ventricles via both the AV node and an accessory pathway (Bundle of Kent). [2] Because the accessory pathway has a shorter refractory period, it allows rapid, haphazard conduction, resulting in a **characteristically irregular RR interval**. [1] ### **Analysis of Incorrect Options** * **A. Irregular RR interval:** This is the hallmark of AF with WPW, not VT. [1] * **C. Broad QRS:** This is a feature of **both** conditions. In VT, the QRS is wide because the impulse originates in the ventricles. In WPW with AF, the QRS is wide due to "pre-excitation" (the impulse bypasses the specialized conduction system via the accessory pathway). [2] * **D. Increased heart rate:** Both conditions typically present with tachycardia (HR >100 bpm), often exceeding 150–200 bpm, so this does not help in differentiation. [1] ### **High-Yield Clinical Pearls for NEET-PG** * **Brugada’s Criteria:** Used to differentiate VT from SVT with aberrancy; however, the presence of an **irregular** wide complex rhythm should immediately make you think of **AF with WPW**. * **Treatment Warning:** In AF with WPW, never use AV nodal blockers (ABCD: **A**denosine, **B**eta-blockers, **C**alcium channel blockers, **D**igoxin). These drugs can paradoxically increase conduction through the accessory pathway, leading to Ventricular Fibrillation. * **Drug of Choice:** Hemodynamically unstable patients require DC cardioversion. For stable AF with WPW, **Procainamide** or **Ibutilide** are preferred.

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