Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 491: A 42-year-old man presents with dizziness on standing. His systolic blood pressure falls by 50 mm Hg and his heart rate is 52/min. What is the likely cause?

A. Congestive heart failure
B. Inferior wall myocardial infarction
C. Pheochromocytoma (Correct Answer)
D. Theophylline toxicity

Explanation: **Explanation:** The clinical presentation describes **orthostatic hypotension** (a drop in systolic BP ≥20 mmHg) accompanied by **inappropriate bradycardia** (lack of compensatory tachycardia) [1]. In **Pheochromocytoma**, while the classic triad is headache, sweating, and palpitations, chronic excess of catecholamines leads to severe **volume depletion** due to pressure natriuresis and chronic vasoconstriction. When the patient stands, the depleted intravascular volume causes a significant drop in blood pressure [2]. The presence of bradycardia (or a lack of tachycardia) in this context is a high-yield NEET-PG finding, often attributed to **baroreceptor resetting** or catecholamine-induced cardiomyopathy/autonomic dysfunction [3]. **Analysis of Incorrect Options:** * **Congestive Heart Failure (CHF):** While CHF can cause hypotension, it typically presents with compensatory tachycardia and signs of fluid overload (edema, JVP elevation), not bradycardia. * **Inferior Wall MI:** While this can cause bradycardia (due to Bezold-Jarisch reflex or SA/AV node ischemia), it presents with acute chest pain and ECG changes, and orthostatic hypotension is not the primary presenting feature. * **Theophylline Toxicity:** This typically causes **tachycardia**, arrhythmias, and seizures due to its phosphodiesterase inhibition and adenosine antagonism. **NEET-PG Clinical Pearls:** * **Rule of 10s for Pheo:** 10% bilateral, 10% malignant, 10% extra-adrenal (Paraganglioma), 10% pediatric, 10% familial. * **Orthostatic Hypotension in Pheo:** Paradoxically, a patient with hypertension who also shows orthostatic hypotension is a classic clue for Pheochromocytoma. * **Pre-op Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) followed by Beta-blockers to avoid an uninhibited alpha-mediated hypertensive crisis.

Question 492: Giant a waves in JVP are seen in which of the following conditions?

A. Tachycardia
B. Atrial ectopic
C. 1st degree heart block
D. Complete heart block (Correct Answer)

Explanation: **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 493: Comment on the ECG finding shown below?

A. Delta wave
B. Epsilon wave (Correct Answer)
C. Prominent U wave
D. Deep Q wave

Explanation: ***Epsilon wave*** - A **small deflection** after the QRS complex that represents **delayed activation** of parts of the right ventricle, pathognomonic for **arrhythmogenic right ventricular cardiomyopathy (ARVC)**. - ARVC involves **fibro-fatty replacement** of right ventricular myocardium, commonly affects **young athletes**, and carries high risk of **sudden cardiac death**. *Delta wave* - Represents **pre-excitation** via an **accessory pathway** in **Wolff-Parkinson-White syndrome**, appearing as a **slurred upstroke** of the QRS complex. - Associated with **short PR interval** and **wide QRS complex**, not the small post-QRS deflection seen in epsilon waves. *Prominent U wave* - A **positive deflection** after the T wave, commonly seen in **hypokalemia**, **bradycardia**, or **quinidine toxicity**. - Appears as a **separate wave** following the T wave, distinct from the small post-QRS epsilon wave pattern. *Deep Q wave* - Represents **myocardial necrosis** in **myocardial infarction**, appearing as **deep negative deflections** at the beginning of the QRS complex. - Indicates **full-thickness myocardial damage** and is unrelated to the conduction abnormalities seen in ARVC.

Question 494: A 55-year-old female presents with Levine sign, hiccups, and vomiting episodes. On examination, HR=50/min with BP =100/60 mm Hg with elevated JVP. ECG technician is yet to arrive. Which coronary artery is likely to be involved?

A. RCA (Correct Answer)
B. LAD
C. LCX
D. Left main coronary artery

Explanation: ### Explanation The clinical presentation points toward an **Inferior Wall Myocardial Infarction (IWMI)** with Right Ventricular (RV) involvement. **1. Why RCA is the correct answer:** * **Levine Sign:** Indicates ischemic chest pain. * **Hiccups and Vomiting:** These are classic "autonomic symptoms" often associated with inferior wall MI due to irritation of the **vagus nerve** (Bezold-Jarisch reflex) and diaphragmatic irritation [2]. * **Bradycardia (HR=50/min):** The **Right Coronary Artery (RCA)** supplies the SA node (in 60% of people) and the AV node (in 90%). Ischemia to the RCA frequently leads to sinus bradycardia or AV blocks [2]. * **Elevated JVP + Hypotension:** This triad (with clear lungs) suggests **Right Ventricular Infarction**, which occurs in nearly 40% of RCA-related inferior MIs [2]. **2. Why other options are incorrect:** * **LAD (Left Anterior Descending):** Usually causes Anterior Wall MI. This typically presents with tachycardia (due to sympathetic activation) and signs of left heart failure (pulmonary edema), not bradycardia or elevated JVP. * **LCX (Left Circumflex):** Supplies the lateral wall. While it can occasionally supply the inferior wall (in left-dominant circulation), the combination of bradycardia and RV involvement is much more characteristic of the RCA [1]. * **Left Main:** Occlusion usually leads to massive anterolateral infarction, cardiogenic shock, and high mortality; it does not typically present with isolated inferior/RV symptoms. **Clinical Pearls for NEET-PG:** * **Bezold-Jarisch Reflex:** Triad of bradycardia, hypotension, and apnea triggered by inferior wall ischemia [3]. * **RV Infarction Management:** Avoid nitrates, diuretics, and morphine (they decrease preload). The treatment of choice is **IV fluids** to maintain right-sided filling pressures. * **ECG Clue:** ST-elevation in Lead III > Lead II strongly suggests RCA over LCX.

Question 495: Which of the following is the most common cause of midsystolic murmur in adults?

A. Aortic stenosis (Correct Answer)
B. Aortic regurgitation
C. Hypertrophic obstructive cardiac myopathy
D. All of the above

Explanation: ### Explanation **1. Why Aortic Stenosis (AS) is Correct:** A midsystolic (ejection systolic) murmur occurs when blood is forced through a narrowed or obstructed outflow tract during the peak of ventricular contraction. **Aortic Stenosis** is the most common cause of this murmur in adults, typically resulting from age-related degenerative calcification (in older adults) or a congenital bicuspid valve (in younger adults) [1]. As the left ventricle contracts, the pressure gradient across the stenotic valve increases, reaching a peak in mid-systole, which creates the characteristic "crescendo-decrescendo" sound [1],[2]. **2. Why the Other Options are Incorrect:** * **B. Aortic Regurgitation:** This produces a **decrescendo early diastolic murmur**, heard best at the left sternal border, as blood flows backward from the aorta into the left ventricle during diastole [3]. * **C. Hypertrophic Obstructive Cardiomyopathy (HOCM):** While HOCM does cause a midsystolic murmur (due to dynamic left ventricular outflow tract obstruction), it is significantly **less common** in the general adult population compared to degenerative aortic stenosis. * **D. All of the above:** Incorrect because the mechanisms and timing of the murmurs for AR and AS are fundamentally different. **3. NEET-PG High-Yield Clinical Pearls:** * **AS Murmur Characteristics:** Best heard at the right second intercostal space; radiates to the **carotids** [1]. * **Dynamic Auscultation:** The murmur of AS **decreases** with Valsalva (less preload = less flow), whereas the murmur of HOCM **increases** with Valsalva. * **Classic Triad of AS (SAD):** **S**yncope, **A**ngina, and **D**yspnea. * **Physical Sign:** Look for *Pulsus Parvus et Tardus* (slow-rising, low-amplitude pulse) in severe AS [1].

Question 496: Which condition is most likely associated with the given ECG tracing?

A. Conn's syndrome
B. Multiple myeloma
C. Renal failure (Correct Answer)
D. SIADH

Explanation: ***Renal failure*** - **Hyperkalemia** from impaired potassium excretion leads to characteristic ECG changes including **peaked T waves**, **widened QRS complexes**, and potential **sine wave** pattern. - Progressive ECG changes occur as potassium levels rise: **peaked T waves** → **PR prolongation** → **QRS widening** → **sine wave** → **asystole**. *Conn's syndrome* - Causes **hypokalemia** due to excess mineralocorticoid activity, leading to **flattened T waves** and **U waves**, not peaked T waves. - Associated with **hypertension** and **metabolic alkalosis**, but ECG changes are opposite to those seen in hyperkalemia. *Multiple myeloma* - Primarily causes **hypercalcemia** which produces **shortened QT intervals** on ECG, not the peaked T waves of hyperkalemia. - May also cause **renal dysfunction** as a secondary effect, but the primary electrolyte abnormality is elevated calcium. *SIADH* - Results in **hyponatremia** which typically does not produce specific characteristic ECG changes like peaked T waves. - May cause **nonspecific ST-T wave changes** in severe cases, but hyperkalemic ECG patterns are not associated with low sodium levels.

Question 497: All of the following predispose to Ischemic Heart Disease except?

A. Smoking
B. Alcoholism (Correct Answer)
C. Sedentary habits
D. Diabetes

Explanation: **Explanation:** Ischemic Heart Disease (IHD) is primarily caused by atherosclerosis, which is driven by a combination of modifiable and non-modifiable risk factors [1]. **Why Alcoholism is the correct answer:** Moderate alcohol consumption (especially red wine) has historically been associated with a "U-shaped" or "J-shaped" curve regarding cardiovascular risk. In moderate amounts, it may increase HDL (good cholesterol) and have anti-platelet effects [2]. While **heavy** alcohol consumption leads to dilated cardiomyopathy, arrhythmias (Holiday Heart Syndrome), and hypertension, it is not traditionally classified as a primary independent risk factor for *atherosclerotic* IHD in the same way that smoking or diabetes are. In the context of standard medical examinations, it is often the "odd one out" compared to definitive metabolic and lifestyle risks. **Analysis of Incorrect Options:** * **Smoking:** This is one of the most potent modifiable risk factors [3]. It causes endothelial dysfunction, increases platelet adhesiveness, and promotes the oxidation of LDL, directly accelerating atherosclerosis. * **Sedentary Habits:** Physical inactivity leads to obesity, insulin resistance, and low HDL levels [2]. Regular exercise is cardioprotective as it improves endothelial function and lowers blood pressure. * **Diabetes Mellitus:** Often considered a "Coronary Artery Disease (CAD) equivalent" [3]. Hyperglycemia leads to advanced glycation end-products (AGEs) that damage the vascular endothelium, making diabetics prone to premature and diffuse IHD. **High-Yield Clinical Pearls for NEET-PG:** * **Major Risk Factors (Framingham):** Age, Male sex, Smoking, Hypertension, Hyperlipidemia, and Diabetes [3]. * **Most common cause of IHD:** Atherosclerosis. * **Hyperhomocysteinemia** and elevated **Lp(a)** are emerging independent risk factors often tested in recent exams. * **Metabolic Syndrome:** A cluster of sedentary-related issues (abdominal obesity, HTN, low HDL, high TG, impaired fasting glucose) that significantly increases IHD risk.

Question 498: What is the most common valvular lesion seen with carcinoid syndrome?

A. Tricuspid stenosis and pulmonic stenosis
B. Tricuspid insufficiency and pulmonic stenosis (Correct Answer)
C. Mitral stenosis and aortic stenosis
D. Mitral insufficiency and aortic stenosis

Explanation: ### Explanation **Underlying Medical Concept** Carcinoid heart disease occurs in approximately 50% of patients with systemic carcinoid syndrome (usually from metastatic neuroendocrine tumors). The pathology is driven by high circulating levels of **serotonin (5-HT)**, which causes plaque-like fibrous endocardial thickening. These plaques predominantly affect the **right side of the heart**. The serotonin causes the tricuspid valve leaflets to become thickened, shortened, and retracted, leading to **Tricuspid Insufficiency (Regurgitation)** [1]. Simultaneously, the pulmonic valve cusps become scarred and immobile, leading to **Pulmonic Stenosis**. **Analysis of Options** * **Option B (Correct):** Serotonin-induced fibrosis typically results in a "fixed" open tricuspid valve (Insufficiency) and a narrowed pulmonic orifice (Stenosis). [1] * **Option A:** While pulmonic stenosis is correct, the tricuspid valve is more commonly incompetent (regurgitant) than stenotic. * **Options C & D:** Left-sided lesions (Mitral/Aortic) are **rare** because the lungs contain **monoamine oxidase (MAO)**, which inactivates serotonin before it reaches the left heart. Left-sided involvement only occurs in the presence of a right-to-left shunt (e.g., PFO) or primary bronchial carcinoids. **NEET-PG High-Yield Pearls** * **Biochemical Marker:** 24-hour urinary **5-HIAA** (metabolite of serotonin) is used for diagnosis. * **Location:** Right-sided lesions are the hallmark. [1] * **Pathognomonic Feature:** Glistening white "carcinoid plaques" on the endocardial surface. * **Management:** Somatostatin analogues (Octreotide) help control symptoms, but definitive treatment for severe valve disease is surgical replacement.

Question 499: Wolff-Parkinson-White (WPW) syndrome is characterized by which of the following electrocardiographic findings?

A. Prolonged PR interval
B. Delta wave (Correct Answer)
C. U wave
D. Heart block

Explanation: **Explanation:** **Wolff-Parkinson-White (WPW) Syndrome** is a pre-excitation syndrome caused by the presence of an accessory pathway (the **Bundle of Kent**) that bypasses the AV node [1]. This allows electrical impulses to reach the ventricles earlier than usual. 1. **Why "Delta wave" is correct:** In WPW, the impulse travels through the accessory pathway faster than the slow-conducting AV node. This results in premature ventricular depolarization, which manifests on an ECG as a slurred upstroke of the QRS complex, known as a **Delta wave** [1]. Because of this pre-excitation, the **PR interval is shortened (<0.12s)** and the **QRS complex is widened** [1], [2]. 2. **Why other options are incorrect:** * **Prolonged PR interval:** This is characteristic of First-degree AV block. In WPW, the PR interval is characteristically *shortened* because the AV nodal delay is bypassed [1]. * **U wave:** This is a small wave following the T wave, most commonly associated with **hypokalemia**, hypercalcemia, or thyrotoxicosis. * **Heart block:** This refers to a delay or interruption in conduction (e.g., AV block), whereas WPW is a state of "accelerated" conduction. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Short PR interval (<120ms), Delta wave, and Wide QRS complex (>120ms) [1]. * **Associated Arrhythmia:** Most commonly associated with AV Reentrant Tachycardia (AVRT) [2]. * **Drug Contraindication:** Avoid **ABCD** drugs (Adenosine, Beta-blockers, Calcium channel blockers, Digoxin) in WPW with Atrial Fibrillation, as they block the AV node and may favor conduction through the accessory pathway, leading to Ventricular Fibrillation [2]. * **Definitive Treatment:** Radiofrequency ablation of the accessory pathway.

Question 500: Which one of the following is of most serious prognostic significance in a patient of essential hypertension?

A. Diastolic blood pressure greater than 130 mmHg
B. Transient ischemic attacks
C. Left ventricular hypertrophy
D. Papilledema and progressive renal failure (Correct Answer)

Explanation: The question assesses the ability to identify features of **Malignant (Accelerated) Hypertension**, which represents the most severe end of the hypertensive spectrum and carries the highest immediate risk of mortality if untreated. **Why Option D is Correct:** The presence of **Papilledema** (Grade IV hypertensive retinopathy) along with **progressive renal failure** (elevated creatinine, proteinuria) defines Malignant Hypertension [1]. This stage indicates widespread **fibrinoid necrosis** of the arterioles and acute target organ damage. Without aggressive management, the prognosis is grave, with a 1-year mortality rate historically exceeding 90% [1]. It represents a medical emergency requiring controlled reduction of blood pressure. **Analysis of Incorrect Options:** * **Option A:** While a diastolic BP >130 mmHg is extremely high, the prognosis in hypertension is determined more by the **extent of target organ damage** than the absolute numerical value of the blood pressure. * **Option B:** Transient Ischemic Attacks (TIAs) are significant indicators of cerebrovascular disease and increased stroke risk, but they do not signify the acute, multi-system failure seen in malignant hypertension [3]. * **Option C:** Left Ventricular Hypertrophy (LVH) is a sign of chronic pressure overload. While it is a strong predictor of long-term cardiovascular events (like HFpEF or MI), it is a compensatory mechanism that develops over years, unlike the acute threat posed by papilledema [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Keith-Wagener-Barker Classification:** Grade IV retinopathy is characterized specifically by papilledema (disc edema). * **Pathology:** The hallmark of malignant hypertension is **Fibrinoid Necrosis** of small arteries and **Onion-skinning** (hyperplastic arteriolosclerosis). * **Management Goal:** In hypertensive emergencies, reduce Mean Arterial Pressure (MAP) by no more than 25% within the first hour to prevent cerebral hypoperfusion. * **Drug of Choice:** IV Labetalol or Nicardipine are commonly used; Nitroprusside is reserved for specific cases due to cyanide toxicity risks.

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Cardiomyopathies

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Pericardial Diseases

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Congenital Heart Disease in Adults

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Cardiology — MCQs

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