Cardiology Practice Questions

Q: Torsade de pointes is caused by:

Hypomagnesemia. **Explanation:** **Torsades de Pointes (TdP)** is a specific form of polymorphic ventricular tachycardia characterized by a "twisting of the points" around the isoelectric line. It occurs in the setting of a **prolonged QT interval** [1], [2]. **Why Hypomagnesemia is correct:** Magnesium acts as a natural calcium channel blocker and is essential for the function of the Na+/K+-ATPase pump. **Hypomagnesemia** (and hypokalemia) leads to impaired repolarization of cardiac myocytes, which prolongs the action potential duration and the QT interval [3]. This creates a substrate for **Early After-Depolarizations (EADs)**. When these EADs reach a threshold, they trigger the rapid, irregular firing characteristic of TdP. Consequently, intravenous Magnesium Sulfate is the first-line treatment for TdP, even in patients with normal serum magnesium levels. **Why the other options are incorrect:** * **Hypermagnesemia:** High magnesium levels actually stabilize the cardiac membrane and are used to *treat* arrhythmias; they do not cause TdP. * **Metabolic Acidosis/Alkalosis:** While severe pH imbalances can affect cardiac excitability, they are not primary or classic triggers for TdP. TdP is specifically linked to electrolyte disturbances (Hypo-K, Hypo-Mg, Hypo-Ca) and drugs that prolong the QT interval. **High-Yield Clinical Pearls for NEET-PG:** * **Drug-induced TdP (ABCDE):** **A**ntiarrhythmics (Class IA, III), **B**iotics (Macrolides, Fluoroquinolones), **C**isapride (Antipsychotics/Antiemetics), **D**epressants (TCAs), **E**lectrolytes (Hypo-K, Hypo-Mg). * **Congenital Long QT Syndromes:** Romano-Ward (Autosomal Dominant, pure cardiac) and Jervell and Lange-Nielsen (Autosomal Recessive, cardiac + sensorineural deafness) [2]. * **Management:** IV Magnesium Sulfate is the drug of choice. If refractory, use overdrive pacing or Isoproterenol to increase heart rate (which shortens the QT interval). Avoid Class IA and III antiarrhythmics.

Q: Which of the following is the preferred antiarrhythmic agent in a patient with cardiac arrest?

Amiodarone. **Explanation:** In the management of cardiac arrest due to **Shockable Rhythms** (Ventricular Fibrillation or Pulseless Ventricular Tachycardia), **Amiodarone** is the first-line antiarrhythmic agent according to the current ACLS (Advanced Cardiovascular Life Support) guidelines. **Why Amiodarone is Correct:** Amiodarone is a Class III antiarrhythmic that acts by blocking potassium channels (prolonging repolarization), but it also possesses Class I, II, and IV properties. In cardiac arrest, it is preferred because clinical trials (like the ALIVE trial) demonstrated that it improves the rate of **ROSC (Return of Spontaneous Circulation)** and survival to hospital admission compared to placebo or lidocaine. It is typically administered as a 300 mg IV/IO bolus after the third unsuccessful shock. **Why Other Options are Incorrect:** * **Lidocaine:** While Lidocaine is an acceptable alternative if Amiodarone is unavailable, it is no longer the primary choice. It is a Class Ib agent that specifically targets ischemic sodium channels. * **Procainamide:** This Class Ia agent is used for stable wide-complex tachycardia. It is not used in cardiac arrest because it requires slow infusion and can cause significant hypotension. * **Atropine:** Previously used for asystole/PEA, it was removed from the cardiac arrest algorithm in 2010 as it showed no survival benefit. It is now primarily used for symptomatic bradycardia. **High-Yield NEET-PG Pearls:** * **Drug of Choice for VF/pVT:** Amiodarone (1st line), Lidocaine (2nd line). * **Amiodarone Side Effects:** Pulmonary fibrosis, thyroid dysfunction (contains iodine), and corneal microdeposits. * **Amiodarone in WPW Syndrome:** It is the drug of choice for stable patients with WPW and atrial fibrillation. * **Maintenance:** After ROSC, an infusion of the successful antiarrhythmic is often started.

Q: A double apical impulse is seen in which condition?

Hypertrophic Obstructive Cardiomyopathy (HOCM). ### Explanation **Correct Answer: A. Hypertrophic Obstructive Cardiomyopathy (HOCM)** In HOCM, the double apical impulse (also known as a **bifid impulse**) occurs due to two distinct mechanical events felt during systole [2]: 1. **First Component:** The initial forceful contraction of the hypertrophied left ventricle. 2. **Second Component:** A sudden interruption of ventricular outflow caused by **Systolic Anterior Motion (SAM)** of the mitral valve against the thickened septum. This creates a "midsystolic dip," followed by a second pressure peak as the ventricle continues to contract against the obstruction. *Note: If a forceful atrial contraction (S4) is also palpable, it can result in a triple apical impulse.* **Why the other options are incorrect:** * **B. Cardiac Tamponade:** The apex beat is typically **faint or impalpable** due to the insulating effect of the surrounding pericardial fluid. * **C. Aortic Regurgitation:** Characterized by a **hyperdynamic (volume-overload)** apex beat that is displaced laterally and inferiorly, but it remains a single, forceful thrust [1] [3]. * **D. Pulmonary Hypertension:** This leads to right ventricular hypertrophy, which typically manifests as a **left parasternal heave**, not a double apical impulse [1]. **NEET-PG High-Yield Pearls for HOCM:** * **Triple Ripple:** A palpable S4 + Double Systolic Impulse (pathognomonic for HOCM) [2]. * **Pulse:** Characterized by **pulsus bisferiens** (a double-peaked arterial pulse). * **Murmur:** A harsh systolic ejection murmur that **increases** with Valsalva or standing (decreased preload) and **decreases** with squatting or handgrip (increased afterload/preload) [2]. * **ECG:** Often shows "dagger-like" Q waves in lateral leads (I, aVL, V5-V6).

Q: An ankle-brachial index (ABI) that suggests increased risk of myocardial infarction would be:

<0.9. The **Ankle-Brachial Index (ABI)** is a non-invasive tool used to screen for Peripheral Arterial Disease (PAD). It is calculated by dividing the higher systolic blood pressure at the ankle (tibialis posterior or dorsalis pedis) by the higher systolic blood pressure in the arm. **Why <0.9 is correct:** An **ABI <0.9** is the diagnostic threshold for PAD. [1] PAD is considered a "coronary artery disease equivalent." Because atherosclerosis is a systemic process, its presence in the lower extremities indicates widespread vascular damage. [1] Patients with an ABI 0.9 (Option C):** An ABI between **0.91 and 1.30** is considered normal. Values in this range indicate healthy blood flow and a lower risk of cardiovascular events. * **>0.6 (Option D):** This range includes normal values (0.9–1.3), which would not suggest an increased risk of MI. **High-Yield Clinical Pearls for NEET-PG:** * **ABI >1.4:** Suggests non-compressible, calcified vessels (commonly seen in **Diabetes Mellitus** and Chronic Kidney Disease). In such cases, a **Toe-Brachial Index (TBI)** should be performed. * **ABI 0.4–0.7:** Associated with moderate PAD and intermittent claudication. [1] * **ABI <0.4:** Associated with severe PAD, rest pain, and critical limb ischemia. [1] * **Gold Standard:** While ABI is the best screening tool, **Digital Subtraction Angiography (DSA)** remains the gold standard for anatomical mapping before intervention.

Q: What is the drug of choice for maintenance therapy in PSVT?

Verapamil. **Explanation:** The management of Paroxysmal Supraventricular Tachycardia (PSVT) is divided into two phases: acute termination and long-term maintenance. **Why Verapamil is the correct answer:** While Adenosine is the drug of choice for the **acute termination** of PSVT, it cannot be used for maintenance due to its extremely short half-life (<10 seconds). For **maintenance therapy** (prophylaxis to prevent recurrences), oral Calcium Channel Blockers (CCBs) like **Verapamil** or Diltiazem are preferred. They act by slowing conduction and prolonging refractoriness in the AV node, effectively preventing the re-entrant circuit that characterizes PSVT. **Analysis of Incorrect Options:** * **Adenosine:** The drug of choice for **acute termination** of PSVT. It causes transient AV block but is unsuitable for maintenance. * **Amiodarone:** A broad-spectrum Class III antiarrhythmic used primarily for ventricular arrhythmias or rhythm control in Atrial Fibrillation. It is not a first-line agent for PSVT maintenance due to its significant side-effect profile (pulmonary fibrosis, thyroid dysfunction). * **Lignocaine:** A Class Ib antiarrhythmic that acts exclusively on ventricular tissues. It has no efficacy in supraventricular arrhythmias like PSVT. **High-Yield Clinical Pearls for NEET-PG:** 1. **Acute Management:** Vagal maneuvers (first-line) $\rightarrow$ IV Adenosine (drug of choice) $\rightarrow$ IV Verapamil/Diltiazem. 2. **Definitive Treatment:** Radiofrequency Ablation (RFA) is the gold standard for permanent cure. 3. **Contraindication:** Avoid Verapamil in PSVT patients with underlying WPW syndrome, as it may paradoxically increase conduction through the accessory pathway, leading to Ventricular Fibrillation.

Q: A patient with heart failure developed recurrent sustained monomorphic ventricular tachycardia. What is/are the appropriate treatment(s)?

Implantable Cardioverter-Defibrillator. **Explanation:** The primary goal in managing a patient with heart failure (HF) and recurrent sustained monomorphic ventricular tachycardia (VT) is the prevention of **Sudden Cardiac Death (SCD)**. **Why ICD is the Correct Answer:** According to current guidelines (ACC/AHA/ESC), an **Implantable Cardioverter-Defibrillator (ICD)** is the treatment of choice for **secondary prevention** of SCD in patients who have experienced sustained VT, especially in the setting of structural heart disease like heart failure [1]. While drugs may reduce the frequency of episodes, only the ICD has been proven to significantly improve survival by providing immediate internal cardioversion/defibrillation during life-threatening arrhythmias [1]. **Analysis of Incorrect Options:** * **A & B (Encainide and Flecainide):** These are Class 1C antiarrhythmics. The landmark **CAST (Cardiac Arrhythmia Suppression Trial)** proved that these drugs actually *increase* mortality in patients with prior myocardial infarction or structural heart disease due to their potent **pro-arrhythmic effects**. They are strictly contraindicated in heart failure. * **D (Beta-blockers):** While beta-blockers are a cornerstone of heart failure therapy and help reduce the burden of VT, they are generally insufficient as a standalone treatment for *recurrent sustained* VT [1]. They are used as adjunctive therapy alongside an ICD. **High-Yield Clinical Pearls for NEET-PG:** * **Amiodarone** is the preferred antiarrhythmic drug for VT in heart failure patients if an ICD is not feasible or to reduce frequent ICD shocks, as it is "neutral" regarding mortality. * **Class 1C drugs** (Flecainide, Propafenone) are for "Normal Hearts" only. * **Primary Prevention:** ICD is also indicated in HF patients with an Ejection Fraction (EF) ≤ 35% and NYHA Class II/III symptoms despite optimal medical therapy [1].

Question 1

Torsade de pointes is caused by:

Accepted Answer

Hypomagnesemia

Answer

Hypermagnesemia

Answer

Metabolic acidosis

Answer

Metabolic alkalosis

Question 2

Which of the following is the preferred antiarrhythmic agent in a patient with cardiac arrest?

Accepted Answer

Amiodarone

Answer

Lidocaine

Answer

Procainamide

Answer

Atropine

Question 3

A double apical impulse is seen in which condition?

Accepted Answer

Hypertrophic Obstructive Cardiomyopathy (HOCM)

Answer

Cardiac tamponade

Answer

Aortic regurgitation

Answer

Pulmonary hypertension

Question 4

A 32-year-old carpenter presents with a history of recurrent chest pain. Sublingual nitroglycerin is prescribed and advised to be taken at the onset of pain. Two weeks later, the patient reports increased chest pain intensity upon taking nitroglycerin. What is the most likely diagnosis?

Accepted Answer

Hypertrophic obstructive cardiomyopathy

Answer

Aortic regurgitation

Answer

Aortic dissection

Answer

Aortic aneurysm

Question 5

An ankle-brachial index (ABI) that suggests increased risk of myocardial infarction would be:

Accepted Answer

<0.9

Answer

<0.6

Answer

>0.9

Answer

>0.6

Question 6

Radiofemoral delay is characteristic of which of the following conditions?

Accepted Answer

Coarctation of the aorta

Answer

Patent ductus arteriosus

Answer

Aortic dissection

Answer

Takayasu's arteritis

Question 7

Which one of the following is an absolute contraindication to the use of a thrombolytic agent in the setting of an acute anterior wall myocardial infarction?

Accepted Answer

History of cerebrovascular accident with hemiparesis one month ago

Answer

Diabetic retinopathy

Answer

Patient's age more than 70 years

Answer

Patient is on warfarin for atrial fibrillation with INR ratio 1.8

Question 8

A 50-year-old man was recently diagnosed with coronary artery disease. There were no added risk factors except for an LDL value of 150-165 mg/dL. What is the single most appropriate drug for initial therapy?

Accepted Answer

Statins

Answer

Gemfibrozil

Answer

Nicotinic acid

Answer

Bile acid binding resins

Question 9

What is the drug of choice for maintenance therapy in PSVT?

Accepted Answer

Verapamil

Answer

Amiodarone

Answer

Lignocaine

Answer

Adenosine

Question 10

A patient with heart failure developed recurrent sustained monomorphic ventricular tachycardia. What is/are the appropriate treatment(s)?

Accepted Answer

Implantable Cardioverter-Defibrillator

Answer

Encainide

Answer

Flecainide

Answer

Beta-blockers

Cardiology — MCQs

Cardiology — MCQs

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