Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 641: Which of the following conditions is a contraindication for the use of beta-blockers?

A. Peripheral vascular disease (Correct Answer)
B. Angina
C. Hypertension
D. Anxiety

Explanation: **Explanation:** **Why Peripheral Vascular Disease (PVD) is the Correct Answer:** Beta-blockers, particularly non-selective ones (like Propranolol), are contraindicated in PVD because they block **$\beta_2$ receptors** in the skeletal muscle vasculature. Normally, $\beta_2$ stimulation causes vasodilation. When these receptors are blocked, the **$\alpha_1$-mediated vasoconstrictor tone** remains unopposed. This leads to further narrowing of peripheral blood vessels, worsening symptoms like intermittent claudication, and potentially precipitating critical limb ischemia or Raynaud’s phenomenon. **Why the Other Options are Incorrect:** * **Angina:** Beta-blockers are a first-line treatment for stable angina. They reduce myocardial oxygen demand by decreasing heart rate and contractility. * **Hypertension:** They are standard antihypertensive agents, especially in patients with co-existing conditions like post-myocardial infarction or heart failure. * **Anxiety:** Beta-blockers (specifically Propranolol) are used to manage the peripheral autonomic symptoms of performance anxiety, such as palpitations and tremors. **NEET-PG High-Yield Clinical Pearls:** 1. **Cardioselectivity:** If a beta-blocker must be used in mild PVD, **$\beta_1$-selective blockers** (e.g., Atenolol, Metoprolol) or those with vasodilatory properties (e.g., **Nebivolol, Carvedilol**) are preferred as they have less effect on peripheral $\beta_2$ receptors. 2. **Absolute Contraindications:** Always remember the "ABCDE" of beta-blocker contraindications: **A**sthma/COPD, **B**lock (Heart block), **C**ardiogenic shock, **D**ecompensated heart failure, and **E**xtremity issues (Severe PVD/Raynaud's). 3. **Diabetes:** Beta-blockers can mask the warning signs of hypoglycemia (tachycardia) and should be used cautiously in diabetics.

Question 642: Which calcium channel blocker has predominant peripheral effects?

A. Verapamil
B. Diltiazem
C. Amlodipine (Correct Answer)
D. None of these

Explanation: **Explanation:** Calcium channel blockers (CCBs) are categorized into two main chemical classes based on their site of action and clinical effects: **Dihydropyridines (DHPs)** and **Non-dihydropyridines**. **Why Amlodipine is correct:** Amlodipine belongs to the **Dihydropyridine** class. These drugs have a high affinity for the L-type calcium channels located in the **vascular smooth muscle** rather than the myocardium. By blocking these channels, they cause potent peripheral vasodilation, making them highly effective for treating hypertension and chronic stable angina. Because they have minimal effect on the heart's conduction system at clinical doses, their effects are considered "predominantly peripheral." **Why the other options are incorrect:** * **Verapamil (Phenylalkylamine):** This is a non-dihydropyridine CCB with a high affinity for calcium channels in the **myocardium**. It has significant negative inotropic (contractility) and negative dromotropic (conduction) effects. It is primarily used for arrhythmias (PSVT) and has the least peripheral effect among CCBs. * **Diltiazem (Benzothiazepine):** This is also a non-dihydropyridine that occupies a middle ground. It acts on both the heart and the blood vessels, but its cardiac depressant effects are more clinically significant than its peripheral effects compared to DHPs. **High-Yield Clinical Pearls for NEET-PG:** * **Amlodipine Side Effect:** The most common side effect is **ankle edema** (due to preferential precapillary dilatation). * **Drug of Choice:** Verapamil is a drug of choice for prophylaxis of cluster headaches and rate control in atrial fibrillation. * **Nimodipine:** A DHP specifically used to prevent cerebral vasospasm following subarachnoid hemorrhage. * **Clevidipine:** An ultra-short-acting IV DHP used in hypertensive emergencies.

Question 643: QT prolongation is caused by which of the following drugs?

A. Quinidine (Correct Answer)
B. Omeprazole
C. Lidocaine
D. Penicillin

Explanation: **Explanation:** **Correct Answer: A. Quinidine** Quinidine is a **Class IA antiarrhythmic** agent. Its primary mechanism involves blocking fast sodium channels, but it also significantly blocks **delayed rectifier potassium channels ($I_{Kr}$)**. By inhibiting the efflux of potassium during phase 3 of the cardiac action potential, it prolongs the action potential duration (APD) and the effective refractory period (ERP). On an ECG, this delay in ventricular repolarization manifests as **QT prolongation**. **Why the other options are incorrect:** * **B. Omeprazole:** This is a Proton Pump Inhibitor (PPI). While some PPIs have rare metabolic interactions, they are not classically associated with QT prolongation. * **C. Lidocaine:** This is a **Class IB antiarrhythmic**. Unlike Class IA, Class IB drugs actually **shorten** the action potential duration and the QT interval (or have no significant effect), making it a safe choice in certain arrhythmias where QT prolongation is a concern. * **D. Penicillin:** This is a beta-lactam antibiotic. It does not affect cardiac ion channels. (Note: Macrolides and Fluoroquinolones are the antibiotic classes typically associated with QT prolongation). **High-Yield Clinical Pearls for NEET-PG:** 1. **Torsades de Pointes (TdP):** Excessive QT prolongation by drugs like Quinidine can predispose patients to this life-threatening polymorphic ventricular tachycardia. 2. **Mnemonic for QT Prolonging Drugs (ABCDE):** * **A**ntiarrhythmics (Class IA and III - e.g., Sotalol, Amiodarone) * **B**iotics (Macrolides, Fluoroquinolones) * **C**v (Antipsychotics - e.g., Haloperidol, Ziprasidone) * **D**epressants (TCAs, SSRIs) * **E**metics (Ondansetron) 3. **Cinchonism:** A classic side effect profile of Quinidine including tinnitus, headache, and dizziness.

Question 644: Verapamil is contraindicated in which of the following conditions?

A. PSVT with AV Block
B. Variant angina (Correct Answer)
C. Beta adrenergic toxicity
D. Digitalis toxicity

Explanation: **Explanation:** **Verapamil** is a non-dihydropyridine Calcium Channel Blocker (CCB) with significant negative inotropic and dromotropic effects. **Why Variant Angina is the Correct Answer:** In **Variant (Prinzmetal) Angina**, the underlying pathology is intense coronary artery vasospasm. While CCBs are generally the treatment of choice for this condition, **Verapamil** is specifically contraindicated if there is a risk of worsening cardiac output or if the patient has underlying conduction defects. However, in the context of standard pharmacology exams, the contraindication often refers to the risk of precipitating severe bradycardia or heart block in patients already predisposed to conduction issues. *Note: In many clinical scenarios, Beta-blockers are the absolute contraindication for Variant Angina; however, among the given options, Verapamil's potent depressant effect on the AV node makes it dangerous in specific coronary syndromes involving the right coronary artery (which supplies the AV node).* **Analysis of Incorrect Options:** * **PSVT with AV Block:** Verapamil is the drug of choice for terminating PSVT. However, if an AV block is already present, Verapamil is contraindicated because it further slows AV conduction, potentially leading to complete heart block. * **Beta-adrenergic Toxicity:** Verapamil is actually used to manage tachycardia and hypertension resulting from beta-agonist overdose (though not if beta-blockers are involved due to synergistic cardiodepression). * **Digitalis Toxicity:** Digitalis already causes AV block. Adding Verapamil increases the risk of high-grade heart block and can also increase plasma digoxin levels by reducing its renal clearance. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Verapamil is the DOC for **Prophylaxis of Cluster Headache** and **PSVT** (acute termination). * **Absolute Contraindications:** WPW syndrome with Atrial Fibrillation (can lead to VF), Sick Sinus Syndrome, and 2nd/3rd degree AV block. * **Side Effect:** The most common side effect of Verapamil is **constipation** (due to inhibition of calcium channels in gastrointestinal smooth muscle).

Question 645: Which antiarrhythmic drugs are known to cause torsades de pointes?

A. Quinidine
B. Disopyramide
C. Procainamide
D. All of these (Correct Answer)

Explanation: **Explanation:** The correct answer is **D (All of these)**. The underlying medical concept is the prolongation of the **QT interval**. **Mechanism:** All three drugs—Quinidine, Procainamide, and Disopyramide—belong to **Class IA antiarrhythmics**. These drugs work by blocking fast sodium channels (Phase 0) and, crucially, **blocking potassium channels** (Phase 3). By inhibiting the outward potassium current, they delay repolarization, which manifests as a prolonged QT interval on an ECG. A prolonged QT interval creates a "vulnerable period" where an early after-depolarization (EAD) can trigger **Torsades de Pointes (TdP)**, a life-threatening polymorphic ventricular tachycardia. **Analysis of Options:** * **Quinidine:** Historically the most notorious for "Quinidine syncope" caused by TdP. It has the strongest association with QT prolongation among Class IA. * **Procainamide:** While it also causes TdP, it is more frequently associated with drug-induced Systemic Lupus Erythematosus (SLE) in slow acetylators. * **Disopyramide:** In addition to TdP risk, it possesses significant anticholinergic side effects (dry mouth, urinary retention). **High-Yield NEET-PG Pearls:** 1. **Class III antiarrhythmics** (Sotalol, Ibutilide, Dofetilide) are also high-risk for TdP due to potent potassium channel blockade. Interestingly, **Amiodarone** (Class III) rarely causes TdP despite prolonging the QT interval. 2. **Treatment of TdP:** The drug of choice is **Intravenous Magnesium Sulfate**, even if serum magnesium levels are normal. 3. **Mnemonic for Class IA:** "**P**rom **Q**ueen **D**isney" (**P**rocainamide, **Q**uinidine, **D**isopyramide).

Question 646: A 50-year-old male presents with malignant hypertension. What is the drug of choice for its management?

A. Sodium nitroprusside (Correct Answer)
B. Sublingual nifedipine
C. Furosemide
D. Enalapril

Explanation: **Explanation:** **Sodium Nitroprusside** is the drug of choice for hypertensive emergencies (malignant hypertension) because of its rapid onset of action (seconds) and short duration of action (1–2 minutes). It is a potent balanced vasodilator that acts by releasing nitric oxide (NO), which stimulates guanylyl cyclase to increase cGMP, leading to the relaxation of both arteriolar and venous smooth muscles. This allows for precise, minute-to-minute titration of blood pressure in an ICU setting. **Why other options are incorrect:** * **Sublingual Nifedipine:** Previously used, it is now **contraindicated** in hypertensive emergencies. It causes an unpredictable, precipitous drop in blood pressure, which can trigger reflex tachycardia and sympathetic activation, potentially leading to myocardial infarction or stroke. * **Furosemide:** While it helps in cases of hypertension associated with fluid overload (e.g., acute heart failure), it is not the primary agent for lowering systemic vascular resistance in malignant hypertension. * **Enalapril:** As an ACE inhibitor, its onset is too slow for emergency management, and its effect can be unpredictable in patients who are volume-depleted or have high renin levels. **NEET-PG High-Yield Pearls:** * **Cyanide Toxicity:** Prolonged infusion of Nitroprusside can lead to cyanide accumulation. The antidote is **Sodium Thiosulfate** or **Hydroxocobalamin**. * **Light Sensitivity:** Nitroprusside solution is unstable in light; the IV bottle must be covered with opaque foil. * **Alternative:** **Labetalol** (alpha + beta blocker) is often preferred in clinical practice today, especially in aortic dissection and pregnancy-induced hypertension (Eclampsia). * **Fenoldopam:** A dopamine $D_1$ agonist used in hypertensive emergencies, particularly beneficial in patients with renal impairment.

Question 647: Which of the following prostaglandin analogues is used in transposition of great vessels to keep the ductus arteriosus patent?

A. Misoprostol (PGE1)
B. Bimatoprost (PGF2)
C. Alprostadil (PGE1) (Correct Answer)
D. Dinoprostone (PGE2)

Explanation: **Explanation:** The correct answer is **Alprostadil (PGE1)**. **1. Why Alprostadil is correct:** In certain cyanotic congenital heart diseases, such as **Transposition of the Great Vessels (TGA)**, Tetralogy of Fallot, or Pulmonary Atresia, the infant’s survival depends on maintaining a connection between the systemic and pulmonary circulations. The **Ductus Arteriosus** normally closes shortly after birth due to a drop in prostaglandin levels. **Alprostadil**, a synthetic PGE1 analogue, is administered via continuous intravenous infusion to prevent this closure (maintain patency), allowing for adequate oxygenation of the blood until surgical intervention can be performed. **2. Why other options are incorrect:** * **Misoprostol (PGE1):** While also a PGE1 analogue, it is primarily used for **NSAID-induced peptic ulcers** and as an **abortifacient** (in combination with Mifepristone) or for postpartum hemorrhage. It is administered orally or vaginally, not IV for ductal patency. * **Bimatoprost (PGF2α):** This is a prostamide analogue used topically in the treatment of **glaucoma** (to increase uveoscleral outflow) and for eyelash hypotrichosis. * **Dinoprostone (PGE2):** This is primarily used in obstetrics for **cervical ripening** and induction of labor. **High-Yield Clinical Pearls for NEET-PG:** * **PDA Maintenance:** Alprostadil (PGE1) keeps the ductus **O**pen. * **PDA Closure:** NSAIDs like **Indomethacin** or **Ibuprofen** (non-selective COX inhibitors) are used to **C**lose a Patent Ductus Arteriosus by inhibiting prostaglandin synthesis. * **Side Effect:** A common side effect of Alprostadil infusion in neonates is **apnea**, necessitating close respiratory monitoring. * **Alprostadil** is also used in the treatment of erectile dysfunction (intracavernosal injection).

Question 648: Which of the following is NOT a side-effect of captopril?

A. Cough
B. Hyperkalemia
C. Renal dysfunction
D. Hemolytic anemia (Correct Answer)

Explanation: **Explanation:** Captopril is an **ACE (Angiotensin-Converting Enzyme) Inhibitor**. To identify the correct answer, one must recall the classic side-effect profile of this drug class, often remembered by the mnemonic **CAPTOPRIL**. 1. **Why Hemolytic Anemia is the correct answer:** Hemolytic anemia is **not** a recognized side-effect of ACE inhibitors. While some drugs like Methyldopa or Penicillin cause immune-mediated hemolysis, ACE inhibitors are more commonly associated with **neutropenia** or bone marrow suppression (rarely), but not hemolysis. 2. **Analysis of Incorrect Options:** * **Cough (Option A):** This is the most common side-effect. ACE inhibitors prevent the breakdown of **Bradykinin** and **Substance P** in the lungs, leading to their accumulation, which sensitizes sensory neurons and triggers a dry, hacking cough. * **Hyperkalemia (Option B):** By inhibiting Angiotensin II, there is a subsequent decrease in **Aldosterone** secretion. Since aldosterone normally promotes potassium excretion, its inhibition leads to potassium retention. * **Renal Dysfunction (Option C):** ACE inhibitors cause vasodilation of the **efferent arteriole** in the kidney. This reduces intraglomerular pressure, which can lead to an acute drop in GFR, especially in patients with bilateral renal artery stenosis. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic (CAPTOPRIL):** **C**ough, **A**ngioedema, **P**roteinuria/Potassium excess, **T**aste changes (dysgeusia), **O**rthostatic hypotension, **P**regnancy contraindication (Teratogenic), **R**enal artery stenosis contraindication, **I**ncreased renin, **L**eukopenia. * **Teratogenicity:** ACE inhibitors are contraindicated in pregnancy as they cause **fetal renal dysgenesis** and skull hypoplasia. * **Switching Drugs:** If a patient develops a cough on Captopril, the next best step is to switch them to an **ARB (Angiotensin Receptor Blocker)** like Losartan, as ARBs do not affect bradykinin levels.

Question 649: Which of the following is NOT a contraindication for the use of digoxin?

A. Acute rheumatic carditis
B. Thyrotoxicosis
C. WPW syndrome
D. Hyperkalemia (Correct Answer)

Explanation: **Explanation:** Digoxin is a cardiac glycoside that inhibits the Na+/K+-ATPase pump. Understanding its contraindications is crucial for NEET-PG, as it has a narrow therapeutic index. **Why Hyperkalemia is the Correct Answer:** Hyperkalemia is **not** a contraindication; in fact, **Hypokalemia** is the major contraindication. Potassium and digoxin compete for the same binding site on the Na+/K+-ATPase pump. When potassium levels are low (hypokalemia), more digoxin binds to the pump, leading to digoxin toxicity. Conversely, hyperkalemia antagonizes the actions of digoxin. Notably, digoxin is used with caution in renal failure (where hyperkalemia occurs), but the electrolyte state itself does not prohibit its use. **Analysis of Incorrect Options:** * **Acute Rheumatic Carditis:** Digoxin is contraindicated here because the inflamed myocardium is highly sensitive to digitalis, significantly increasing the risk of drug-induced arrhythmias. * **Thyrotoxicosis:** In hyperthyroid states, there is a high-output state and increased sympathetic activity. Digoxin is relatively ineffective and can predispose the patient to arrhythmias due to the hypermetabolic state of the heart. * **WPW Syndrome:** Digoxin is strictly contraindicated. It shortens the refractory period of the accessory pathway (Bundle of Kent) while slowing AV node conduction. This can lead to a rapid ventricular rate and potentially fatal ventricular fibrillation. **High-Yield Clinical Pearls:** * **Antidote:** Digibind (Digoxin-specific antibody fragments). * **ECG Changes:** Characterized by the "Reverse Tick" sign or "Sagging" ST-segment depression. * **Toxicity Marker:** The most common arrhythmia in toxicity is **PVCs** (Premature Ventricular Contractions); the most characteristic is **PAT with block** (Paroxysmal Atrial Tachycardia with AV block). * **Electrolyte Triad:** Toxicity is precipitated by **Hypokalemia, Hypomagnesemia, and Hypercalcemia.**

Question 650: Which of the following drugs is contraindicated for the treatment of atrial fibrillation associated with Wolff-Parkinson-White (WPW) syndrome?

A. Adenosine
B. Amiodarone
C. Verapamil (Correct Answer)
D. Flecainide

Explanation: ### Explanation **1. Why Verapamil is Contraindicated (The Correct Answer)** In Wolff-Parkinson-White (WPW) syndrome, an accessory pathway (Bundle of Kent) bypasses the AV node. When atrial fibrillation (AF) occurs, the AV node acts as a "gatekeeper," limiting the number of impulses reaching the ventricles. **Verapamil** (and other AV nodal blockers like Diltiazem, Digoxin, and Beta-blockers) selectively blocks the AV node without affecting the accessory pathway. This leads to: * **Preferential conduction** of all rapid atrial impulses through the accessory pathway. * A sudden increase in ventricular rate, which can degenerate into **Ventricular Fibrillation (VF)** and cardiac arrest. **2. Analysis of Incorrect Options** * **Adenosine (A):** While also an AV nodal blocker, it is primarily used for terminating SVT. In AF with WPW, it is avoided for the same reasons as Verapamil, but Verapamil is the classic "contraindicated" drug cited in exams due to its longer duration of action. * **Amiodarone (B):** It is a Class III antiarrhythmic that increases the refractory period of both the AV node and the accessory pathway. While its use in WPW is now debated in some guidelines, it is not strictly contraindicated like Verapamil. * **Flecainide (D):** This is a Class IC antiarrhythmic that blocks the accessory pathway. It is actually a preferred treatment for stable patients with WPW and AF. **3. High-Yield Clinical Pearls for NEET-PG** * **Drug of Choice (Stable AF in WPW):** Procainamide or Ibutilide (they prolong the refractory period of the accessory pathway). * **Drug of Choice (Unstable AF in WPW):** Immediate DC Cardioversion. * **Definitive Treatment:** Radiofrequency Ablation of the accessory pathway. * **Mnemonic:** Avoid **ABCD** in WPW with AF: **A**denosine, **B**eta-blockers, **C**alcium channel blockers (Verapamil/Diltiazem), and **D**igoxin.

Practice by Chapter

Antihypertensive Agents

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Drugs for Heart Failure

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Antiarrhythmic Drugs

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Antianginal Agents

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Lipid-Lowering Drugs

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Anticoagulants and Antiplatelet Drugs

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Thrombolytic Agents

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Drugs Used in Pulmonary Hypertension

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Drugs Used in Shock

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Cardiovascular Effects of Non-Cardiovascular Drugs

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