Cardiology Practice Questions

Q: A patient with myocardial infarction presents with nausea, vomiting, epigastric pain, and bradycardia. ECG shows a first-degree heart block. What is the most commonly involved coronary artery in this scenario?

Right coronary artery. **Explanation:** The clinical presentation described—nausea, vomiting, epigastric pain, bradycardia, and heart block—is classic for an **Inferior Wall Myocardial Infarction (IWMI)**. **1. Why the Right Coronary Artery (RCA) is correct:** * **Anatomy:** In approximately 80–85% of individuals (right-dominant circulation), the RCA gives off the posterior descending artery, which supplies the inferior wall of the left ventricle. * **Conduction System:** The RCA supplies the **SA node** (in 60% of cases) and the **AV node** (in 90% of cases). Ischemia to the RCA often leads to bradyarrhythmias and AV blocks (like the first-degree block mentioned) [3]. * **Bezold-Jarisch Reflex:** Ischemia of the inferior wall stimulates vagal afferent fibers, leading to the "Vagal Triad" of hypotension, bradycardia, and nausea/vomiting [2]. **2. Why the other options are incorrect:** * **Left Anterior Descending (LAD):** Supplies the anterior wall and septum. LAD infarcts typically present with tachycardia (due to sympathetic surge) and bundle branch blocks, rather than bradycardia. * **Left Circumflex (LCx):** Supplies the lateral wall. While it can supply the inferior wall in "left-dominant" individuals (10%), it is statistically less common than the RCA [1]. * **Oblique Artery:** This is a small branch (e.g., the oblique vein of Marshall or small atrial branches) and is not a major epicardial vessel responsible for MI. **High-Yield Clinical Pearls for NEET-PG:** * **Right Ventricular MI:** Always suspect this in IWMI patients with hypotension and clear lungs. **Avoid Nitrates** in these patients as they are preload-dependent. * **ECG Leads:** Inferior wall MI is seen in leads **II, III, and aVF** [1]. * **Autonomic Association:** Inferior MI = Parasympathetic (Vagal) signs; Anterior MI = Sympathetic signs [2].

Q: Which of the following is NOT true about Hypertrophic Obstructive Cardiomyopathy?

Beta-2 agonists are useful. Hypertrophic Obstructive Cardiomyopathy (HOCM) is characterized by a dynamic pressure gradient in the Left Ventricular Outflow Tract (LVOT). The severity of this obstruction is inversely proportional to the **Left Ventricular (LV) volume**. Anything that decreases LV volume (decreased preload/afterload) or increases contractility will worsen the obstruction [1]. **Why Option A is the correct answer (False statement):** Beta-2 agonists (like Salbutamol) are **contraindicated** in HOCM. They cause peripheral vasodilation (decreasing afterload) and have mild positive inotropic effects. Both actions decrease the LV end-diastolic volume and increase the LVOT gradient, thereby worsening the obstruction and symptoms. **Analysis of other options:** * **Option B:** Asymmetrical Septal Hypertrophy (ASH) is the hallmark of HOCM, where the interventricular septum is significantly thicker than the posterior wall (Ratio >1.3:1) [1]. * **Option C:** The obstruction is "dynamic" because it varies with the cardiac cycle and loading conditions, often involving the **Systolic Anterior Motion (SAM)** of the mitral valve. * **Option D:** Passive leg raising increases venous return (preload). Increased LV volume pushes the septum away from the mitral valve, widening the LVOT and **improving** (decreasing) the murmur intensity. **High-Yield Clinical Pearls for NEET-PG:** 1. **Murmur Dynamics:** The HOCM murmur (harsh systolic) **increases** with Valsalva and standing (decreased preload) and **decreases** with Squatting and Handgrip (increased preload/afterload). 2. **Drug of Choice:** Beta-blockers (e.g., Metoprolol) are the first-line treatment as they increase diastolic filling time and decrease contractility. 3. **Avoid:** Nitrates, Diuretics, and ACE inhibitors, as they reduce preload/afterload and worsen the gradient [1].

Q: A patient develops Mitral Regurgitation following myocardial infarction. The likely cause for this complication is

Rupture of chorda tendinae. **Explanation:** Acute Mitral Regurgitation (MR) following a Myocardial Infarction (MI) is a critical mechanical complication. The correct answer is **Rupture of chordae tendineae** (or more commonly, the **papillary muscle** to which they attach) [1]. **Why Option B is Correct:** During an MI, the blood supply to the papillary muscles is compromised. The **posteromedial papillary muscle** is most vulnerable because it has a single blood supply (usually the Right Coronary Artery), whereas the anterolateral muscle has dual supply. Ischemia leads to necrosis and subsequent rupture of the papillary muscle or its chordae tendineae. This results in a "flail leaflet," causing acute, severe MR and rapid-onset pulmonary edema [1]. **Why Other Options are Incorrect:** * **Option A:** Heart valves are endocardial structures and do not "infarct" directly; they dysfunction due to damage to the supporting apparatus (muscles/chordae). * **Option C:** While ventricular dilatation (remodeling) can cause "functional MR" by stretching the mitral annulus, this is typically a **chronic** process rather than an acute post-MI complication [1]. * **Option D:** Atrial fibrillation can occur post-MI and may worsen MR due to loss of atrial kick and annular dilation, but it is not the primary structural cause of post-MI MR [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Papillary muscle rupture typically occurs **2 to 7 days** post-MI. * **Clinical Sign:** A new-onset, harsh **pansystolic murmur** at the apex radiating to the axilla [1]. * **Diagnosis:** Transthoracic or Transesophageal Echocardiography is the gold standard. * **Management:** This is a surgical emergency. Stabilize with afterload reducers (Nitroprusside) or an Intra-aortic Balloon Pump (IABP) before definitive surgery.

Q: Cardiac tamponade causes pulsus:

Paradoxus. ### Explanation **Correct Answer: C. Paradoxus** **Mechanism of Pulsus Paradoxus in Cardiac Tamponade:** Pulsus paradoxus is defined as an exaggerated drop in systolic blood pressure (>10 mmHg) during inspiration. In cardiac tamponade, the heart is compressed by fluid within a non-compliant pericardial sac [1]. During inspiration, increased venous return to the right ventricle (RV) causes the RV to expand. Due to the fixed space, the RV pushes the interventricular septum toward the left ventricle (LV). This "ventricular interdependence" reduces LV filling and stroke volume, leading to a significant drop in systemic blood pressure. **Analysis of Incorrect Options:** * **A. Pulsus Alternans:** Characterized by alternating strong and weak beats with a regular rhythm. It is a hallmark of **severe Left Ventricular Failure (LVF)**. * **B. Pulsus Bigemini:** A rhythm where a normal beat is followed by a premature ventricular contraction (PVC). It is commonly seen in **Digoxin toxicity**. * **C. Pulsus Parvus (et Tardus):** Refers to a pulse that is small in amplitude and late/slow to rise. This is the classic finding in **Aortic Stenosis**. **NEET-PG High-Yield Pearls:** * **Beck’s Triad (Tamponade):** Hypotension, Jugular Venous Distension (JVD), and Muffled heart sounds. * **ECG Finding:** Electrical Alternans (alternating QRS amplitude due to the heart "swinging" in fluid) [1]. * **JVP Finding:** Prominent ‘x’ descent with an **absent or diminished ‘y’ descent** (distinguishes it from Constrictive Pericarditis, where ‘y’ is prominent). * **Reverse Pulsus Paradoxus:** Seen in Hypertrophic Obstructive Cardiomyopathy (HOCM) and patients on positive pressure ventilation.

Q: What is the most common cause of sudden arrhythmic death?

Myocardial infarction. **Explanation:** **Why Myocardial Infarction (MI) is the correct answer:** Sudden Cardiac Death (SCD) is most frequently caused by lethal ventricular arrhythmias, specifically **Ventricular Fibrillation (VF)** [1]. The most common underlying substrate for these arrhythmias is **Coronary Artery Disease (CAD)**. Acute myocardial infarction or acute myocardial ischemia triggers an electrical instability in the myocardium, leading to disorganized electrical activity (VF) and immediate circulatory collapse [2]. Statistically, CAD/MI accounts for approximately 70-80% of all sudden cardiac deaths in the adult population. **Analysis of Incorrect Options:** * **B. Aortic Stenosis:** While severe aortic stenosis is a known cause of SCD (due to exertional syncope or arrhythmias), it is far less common than ischemic heart disease. * **C. Dilated Cardiomyopathy (DCM):** DCM is a significant cause of arrhythmic death, particularly in younger patients or those with low ejection fractions, but it ranks second to CAD in overall prevalence. * **D. Electrolyte Abnormalities:** Hypokalemia and hypomagnesemia can predispose a patient to arrhythmias (like Torsades de Pointes), but they are usually "triggers" or exacerbating factors rather than the primary structural cause of death in the general population [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of SCD overall:** Coronary Artery Disease (MI) [2]. * **Most common cause of SCD in young athletes (<35 years):** Hypertrophic Cardiomyopathy (HCM) in the US; Arrhythmogenic Right Ventricular Dysplasia (ARVD) in some European regions. * **Most common arrhythmia in the first hour of MI:** Ventricular Fibrillation [3]. * **Timeframe:** SCD is defined as death occurring within 1 hour of the onset of symptoms (witnessed) or within 24 hours of being seen alive and stable (unwitnessed).

Q: QT prolongation is seen in all except?

Digitalis toxicity. The QT interval represents the duration of ventricular depolarization and repolarization. A prolonged QT interval is clinically significant as it predisposes patients to Torsades de Pointes [1]. Digitalis (Digoxin) acts by inhibiting the Na+/K+ ATPase pump, which leads to an increase in intracellular calcium. This results in a shortening of the action potential duration and, consequently, a shortened QT interval [2]. A characteristic ECG finding in digitalis effect is the "reverse tick" or "sagging" ST-segment depression, not QT prolongation. Analysis of Incorrect Options: * Hypothermia (Option A): Severe hypothermia causes a generalized slowing of cardiac conduction, leading to prolongation of all ECG intervals (PR, QRS, and QT). It is also classically associated with Osborn (J) waves. * Hypocalcemia (Option C): Low serum calcium levels prolong Phase 2 of the cardiac action potential. This specifically lengthens the ST segment, thereby prolonging the QT interval. (Conversely, Hypercalcemia shortens it). * Romano-Ward Syndrome (Option D): This is the most common form of Congenital Long QT Syndrome (LQTS) [1]. It is inherited in an autosomal dominant fashion and is characterized by a prolonged QT interval without deafness (unlike Jervell and Lange-Nielsen syndrome, which includes sensorineural deafness). High-Yield NEET-PG Pearls: 1. Mnemonic for Short QT: "Digoxin and Hyper-calcemia/kalemia/thermia." 2. Drugs causing Prolonged QT: Class IA and III Anti-arrhythmics, Macrolides, Antipsychotics, and TCAs. 3. Formula: The QT interval is heart-rate dependent; the Bazett formula ($QTc = QT / \sqrt{RR}$) is used to calculate the corrected QT interval.

Q: Which of the following biomarkers has been shown to correlate best with pulmonary vascular resistance in patients with heart failure?

Endothelin-1 (ET-1). ### Explanation **Correct Answer: C. Endothelin-1 (ET-1)** **Why Endothelin-1 is correct:** Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor produced by vascular endothelial cells [1]. In patients with heart failure (HF), ET-1 levels are significantly elevated due to neurohormonal activation. Unlike natriuretic peptides, which primarily reflect ventricular stretch and volume status, **ET-1 levels correlate most strongly with pulmonary vascular resistance (PVR)** and pulmonary artery wedge pressure. ET-1 contributes to the pathophysiology of HF by causing systemic and pulmonary vasoconstriction, promoting myocardial hypertrophy, and inducing vascular remodeling. It is considered a strong independent predictor of mortality and the severity of pulmonary hypertension in HF patients. **Why other options are incorrect:** * **A & B (BNP and ANP):** While BNP and ANP are gold-standard biomarkers for diagnosing heart failure and assessing ventricular wall stress (volume/pressure overload), they correlate better with **filling pressures** (like LVEDP) rather than specific vascular resistance [2, 3]. They are "vasodilatory" peptides, acting in opposition to the effects of ET-1 [3]. * **D (Endothelin-2):** ET-2 is an isomer of endothelin, but it is primarily produced in the kidneys and intestine [1]. It does not play a significant role in the cardiovascular hemodynamics of heart failure compared to ET-1. **High-Yield Clinical Pearls for NEET-PG:** * **ET-1** is the most potent vasoconstrictor known (10x more potent than Angiotensin II) [1]. * **Bosentan** is a dual endothelin receptor antagonist (ET-A and ET-B) used in Pulmonary Arterial Hypertension (PAH). * **BNP** has a high **Negative Predictive Value (NPV)**; if BNP is normal, heart failure is highly unlikely [2]. * **Neprilysin inhibitors** (e.g., Sacubitril) work by preventing the breakdown of ANP/BNP, thereby promoting vasodilation and natriuresis.

Question 1

A patient with myocardial infarction presents with nausea, vomiting, epigastric pain, and bradycardia. ECG shows a first-degree heart block. What is the most commonly involved coronary artery in this scenario?

Accepted Answer

Right coronary artery

Answer

Left anterior descending artery

Answer

Oblique artery

Answer

Left circumflex coronary artery

Question 2

Which of the following is NOT true about Hypertrophic Obstructive Cardiomyopathy?

Accepted Answer

Beta-2 agonists are useful

Answer

Asymmetrical hypertrophy of the septum

Answer

Dynamic left ventricular outflow obstruction

Answer

The condition improves on passive leg raising

Question 3

A patient develops Mitral Regurgitation following myocardial infarction. The likely cause for this complication is

Accepted Answer

Rupture of chorda tendinae

Answer

Infarction involving the valve

Answer

Dilatation of the ventricle

Answer

Atrial fibrillation

Question 4

A patient is alert and oriented and has a BP of 110/60. In which patient would adenosine constitute appropriate initial therapy?

Accepted Answer

A 65-year-old woman with known ischemic disease and narrow complex tachycardia

Answer

A 65-year-old man with no ischemic heart disease and wide complex tachycardia

Answer

A 25-year-old woman with known preexcitation syndrome and narrow complex tachycardia

Answer

A 28-year-old man with known preexcitation syndrome and wide complex tachycardia

Question 5

Cardiac tamponade causes pulsus:

Accepted Answer

Paradoxus

Answer

Alternans

Answer

Bigemini

Answer

Parvus

Question 6

Which of the following is seen in a patient with tricuspid incompetence?

Accepted Answer

Hepatic pulsation

Answer

A wave in JVP

Answer

Mid diastolic murmur

Answer

Normal cardiac output

Question 7

What is the most common cause of sudden arrhythmic death?

Accepted Answer

Myocardial infarction

Answer

Aortic stenosis

Answer

Dilated cardiomyopathy

Answer

Electrolyte abnormalities

Question 8

Which of the following is NOT a cause of elevated jugular venous pressure with hypotension?

Accepted Answer

Second-degree atrioventricular block

Answer

Cardiac tamponade

Answer

Right ventricular myocardial infarction

Answer

Heart failure

Question 9

QT prolongation is seen in all except?

Accepted Answer

Digitalis toxicity

Answer

Hypothermia

Answer

Hypocalcemia

Answer

Romano-Ward syndrome

Question 10

Which of the following biomarkers has been shown to correlate best with pulmonary vascular resistance in patients with heart failure?

Accepted Answer

Endothelin-1 (ET-1)

Answer

Brain Natriuretic Peptide (BNP)

Answer

Atrial Natriuretic Peptide (ANP)

Answer

Endothelin-2 (ET-2)

Cardiology — MCQs

Cardiology — MCQs

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