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Quizzes > Health & Medicine > Diseases & Conditions

Pharmacotherapy of Arrhythmia Quiz: Test Your Knowledge!

Think you know antiarrhythmic drugs? Take the arrhythmia quiz now!

Difficulty: Moderate
2-5mins
Learning OutcomesCheat Sheet
paper art style heart shape with ECG waveform and arrhythmia quiz title on golden yellow background.

Ready to elevate your expertise with our arrhythmia test online? This interactive arrhythmia quiz is crafted for medical students, nurses, pharmacists, and cardiology enthusiasts eager to assess their mastery of antiarrhythmic drugs test questions and strengthen their grasp on pharmacotherapy of arrhythmia in real-world scenarios. From identifying class effects to dosing considerations, you'll tackle ECG interpretation, drug mechanisms, and potential adverse reactions in this comprehensive heart rhythm quiz. If you're curious how you measure up, dive into our arrhythmias quiz or take on the cardiac drugs quiz for an extra challenge. Prove you can ace this test - start the challenge now!

Which class of antiarrhythmic drugs primarily blocks sodium channels in cardiac myocytes?
Class I
Class II
Class III
Class IV
Class I antiarrhythmics exert their effect by blocking the fast voltage-gated sodium channels in cardiac myocytes, slowing phase 0 depolarization and conduction velocity. They are subdivided into IA, IB, and IC based on their effects on action potential duration. Class IA also prolongs action potential duration, while IB shortens it and IC has little effect. Merck Manual
Which of the following is a Class III antiarrhythmic agent?
Amiodarone
Verapamil
Lidocaine
Propranolol
Amiodarone is a Class III antiarrhythmic that primarily blocks potassium channels, prolonging repolarization and action potential duration. It also has effects on sodium channels, beta-adrenergic receptors, and calcium channels. Its multi-channel blocking properties contribute to its broad antiarrhythmic activity. NCBI Bookshelf
Beta-blockers work by antagonizing which type of receptor in cardiac tissue?
Beta-1 adrenergic receptors
Alpha-1 adrenergic receptors
Voltage-gated sodium channels
L-type calcium channels
Beta-blockers, classified as Class II antiarrhythmics, reduce sympathetic stimulation by blocking beta-1 adrenergic receptors in the heart. This leads to decreased heart rate, reduced AV nodal conduction, and decreased contractility. Beta-1 selective agents like metoprolol preferentially target cardiac receptors. Merck Manual
Which drug is considered first-line for acute management of ventricular arrhythmias post-myocardial infarction?
Lidocaine
Procainamide
Amiodarone
Flecainide
Intravenous lidocaine (Class IB) is often used as first-line therapy for acute ventricular arrhythmias following myocardial infarction due to its rapid onset and selective action on ischemic tissue. It shortens action potential duration and has minimal hemodynamic effects. Amiodarone may be used if lidocaine is ineffective or contraindicated. Merck Manual
Which of the following is a Class IV antiarrhythmic drug?
Verapamil
Quinidine
Esmolol
Mexiletine
Class IV antiarrhythmics refer to L-type calcium channel blockers, including verapamil and diltiazem. These agents slow AV nodal conduction and are used for rate control in supraventricular tachycardias. They do not directly affect sodium channels or action potential duration in ventricular tissue. NCBI Bookshelf
Sotalol is classified as which Vaughan-Williams class of antiarrhythmic?
Class III
Class I
Class II
Class IV
Sotalol exhibits Class III activity by blocking potassium channels and prolonging the action potential and refractory period. It also has nonselective beta-blocker (Class II) properties but is primarily designated as a Class III agent. Its mixed actions make it useful for both atrial and ventricular arrhythmias. Merck Manual
Which antiarrhythmic drug can cause a lupus-like syndrome with chronic use?
Procainamide
Amiodarone
Lidocaine
Metoprolol
Procainamide (Class IA) can induce a reversible lupus-like syndrome after prolonged therapy, characterized by arthralgia, rash, and antinuclear antibodies. The risk increases with higher cumulative doses and longer treatment duration. Other Class IA drugs do not typically cause this reaction. NCBI Bookshelf
Which agent selectively blocks potassium channels, prolonging repolarization without significant sodium channel effects?
Dofetilide
Quinidine
Atenolol
Verapamil
Dofetilide is a pure Class III antiarrhythmic that selectively inhibits the rapid component of the delayed rectifier potassium current (Ikr), leading to prolonged repolarization and QT interval without major sodium channel blockade. It is used for conversion and maintenance of sinus rhythm in atrial fibrillation and flutter. NCBI Bookshelf
Which of the following is a well-known adverse effect of amiodarone therapy?
Thyroid dysfunction
Hypoglycemia
Renal failure
Hyperkalemia
Amiodarone contains iodine and can cause both hypo- and hyperthyroidism due to its effects on thyroid hormone metabolism and gland function. End-organ toxicities also include pulmonary fibrosis and hepatic injury. Thyroid function tests are routinely monitored during therapy. Merck Manual
Which antiarrhythmic agent is considered relatively safe for use during pregnancy?
Lidocaine
Amiodarone
Sotalol
Dronedarone
Lidocaine (Class IB) is commonly used in pregnant patients when necessary for ventricular arrhythmias due to its minimal placental transfer and established safety profile. Agents such as amiodarone are generally avoided because of potential fetal thyroid and developmental toxicities. Dosing adjustments may still be required. UpToDate
Which beta-blocker has an ultra-short half-life and is often used intravenously for acute rate control in supraventricular tachycardia?
Esmolol
Metoprolol
Propranolol
Atenolol
Esmolol (Class II) is an ultra-short-acting beta-1 selective blocker with a half-life of approximately 9 minutes, making it ideal for acute intravenous rate control in supraventricular tachycardias. Its rapid onset and offset allow for tight titration and minimal long-term effects. It is metabolized by red blood cell esterases. Merck Manual
Class IA antiarrhythmic drugs have what primary effect on cardiac action potential?
Moderate sodium channel blockade with prolonged action potential duration
Strong sodium channel blockade with shortened action potential
Beta-adrenergic blockade with no change in duration
Calcium channel blockade with slurred phase 4
Class IA agents such as procainamide and quinidine moderately block sodium channels and also block potassium channels, leading to a prolongation of action potential duration and the effective refractory period. They slow conduction and lengthen repolarization. This distinguishes them from IB (which shorten APD) and IC (which have minimal effect on APD). NCBI Bookshelf
Which characteristic adverse effect is classically associated with quinidine therapy?
Cinchonism
Red man syndrome
Gynecomastia
Gingival hyperplasia
Quinidine can cause cinchonism, a syndrome characterized by tinnitus, headache, nausea, and visual disturbances. It is named after the bark of the cinchona tree from which quinidine is derived. Other adverse effects include QT prolongation and torsades de pointes. Merck Manual
Which antiarrhythmic is contraindicated in patients with significant structural heart disease due to increased mortality risk?
Flecainide
Amiodarone
Digoxin
Sotalol
Flecainide (Class IC) has been associated with proarrhythmic events and increased mortality in patients with structural heart disease, as demonstrated in the CAST trial. It produces strong sodium channel blockade without prolonging action potential duration. It is reserved for patients without significant ventricular dysfunction. NCBI Bookshelf
What is the primary mechanism by which Class II antiarrhythmic drugs exert their effect?
Decreasing cAMP and AV nodal conduction
Blocking fast sodium channels
Inhibiting delayed rectifier potassium current
Blocking L-type calcium channels
Class II antiarrhythmics (beta-blockers) reduce sympathetic tone by antagonizing beta-1 receptors, leading to decreased cAMP levels, reduced calcium influx, slowed AV nodal conduction, and decreased heart rate. They do not directly block sodium or potassium channels. Merck Manual
Which of the following is a non-dihydropyridine calcium channel blocker used as a Class IV antiarrhythmic?
Verapamil
Amlodipine
Nimodipine
Nicardipine
Verapamil is a non-dihydropyridine calcium channel blocker that specifically targets cardiac L-type channels, slowing AV nodal conduction. Dihydropyridines like amlodipine and nicardipine preferentially act on vascular smooth muscle. Nimodipine is used primarily for cerebral vasospasm. NCBI Bookshelf
Which Class III antiarrhythmic requires careful renal dosing adjustments due to primary renal excretion?
Dofetilide
Amiodarone
Ibutilide
Sotalol
Dofetilide is almost exclusively eliminated by the kidneys and requires dose adjustment based on creatinine clearance to avoid excessive QT prolongation and torsades de pointes. Sotalol also has renal excretion but less selectively requires adjustments. Amiodarone is hepatically metabolized. NCBI Bookshelf
Which intravenous electrolyte is first-line therapy for torsades de pointes associated with prolonged QT interval?
Magnesium sulfate
Calcium chloride
Potassium chloride
Sodium bicarbonate
Intravenous magnesium sulfate is the treatment of choice for torsades de pointes, even in patients with normal serum magnesium. It stabilizes cardiac membranes, suppresses early afterdepolarizations, and shortens the QT interval. Other electrolytes may be corrected as needed. Merck Manual
Which drug is used for acute pharmacological conversion of atrial fibrillation to sinus rhythm?
Ibutilide
Esmolol
Metoprolol
Verapamil
Ibutilide is a Class III antiarrhythmic approved for acute chemical cardioversion of atrial fibrillation and flutter by prolonging action potential duration and disrupting reentrant circuits. It acts rapidly when given intravenously. Rate control agents like beta-blockers and calcium channel blockers are not effective for conversion. NCBI Bookshelf
Which antiarrhythmic drug is most commonly associated with pulmonary fibrosis as a serious adverse effect?
Amiodarone
Quinidine
Verapamil
Procainamide
Pulmonary fibrosis is a well-documented, potentially fatal complication of chronic amiodarone therapy due to pulmonary interstitial inflammation and fibrosis. Regular pulmonary function testing and chest imaging are recommended for long-term users. Other antiarrhythmics have different organ-specific toxicities. Merck Manual
Which Class IB antiarrhythmic is preferred for treating ventricular arrhythmias in the setting of digitalis toxicity?
Lidocaine
Procainamide
Amiodarone
Sotalol
Lidocaine is the drug of choice for managing ventricular arrhythmias caused by digitalis toxicity because it preferentially binds to ischemic or depolarized Purkinje and ventricular tissue, suppressing ectopic pacemakers without depressing contractility significantly. Other agents may exacerbate digitalis-induced arrhythmias. NCBI Bookshelf
Which antiarrhythmic exhibits both nonselective beta-blockade and potassium channel-blocking (Class III) properties?
Sotalol
Metoprolol
Diltiazem
Flecainide
Sotalol is unique in that it has nonselective beta-blocker activity (Class II) and prolongs repolarization by blocking potassium channels (Class III). This dual mechanism makes it effective for both rate control and rhythm management in atrial and ventricular arrhythmias. Dose adjustments are needed in renal impairment. NCBI Bookshelf
How does dronedarone differ structurally and clinically from amiodarone?
It lacks iodine moieties, reducing thyroid toxicity
It has a longer half-life and increased tissue accumulation
It is more lipophilic, leading to higher pulmonary risk
It exclusively blocks sodium channels
Dronedarone is an analog of amiodarone but lacks iodine atoms, which significantly reduces thyroid toxicity and tissue accumulation. It retains multi-channel blocking properties but is less effective and has a shorter half-life. However, dronedarone still requires monitoring for hepatic and cardiac side effects. Merck Manual
Which antiarrhythmic drug classically prolongs both QRS duration and QT interval on the ECG?
Quinidine
Lidocaine
Sotalol
Verapamil
Quinidine (Class IA) moderately blocks sodium channels, slowing conduction and widening the QRS, and also blocks potassium channels, prolonging repolarization and the QT interval. Class IB drugs like lidocaine do not significantly affect QRS or QT, and Class III drugs primarily affect QT. NCBI Bookshelf
Which Vaughan-Williams class exhibits strong sodium channel blockade with minimal effect on action potential duration?
Class IC
Class IA
Class IB
Class III
Class IC agents such as flecainide and propafenone produce strong sodium channel blockade, markedly slowing conduction (phase 0) with little to no effect on action potential duration or repolarization. This distinguishes them from Class IA (which prolong APD) and Class IB (which shorten APD). Merck Manual
Co-administration of grapefruit juice can increase plasma levels of which antiarrhythmic agent by inhibiting CYP3A4?
Diltiazem
Amiodarone
Lidocaine
Metoprolol
Grapefruit juice inhibits intestinal CYP3A4, leading to increased bioavailability and plasma concentration of diltiazem, a calcium channel blocker and Class IV antiarrhythmic. This interaction can enhance pharmacologic effects and risks, such as hypotension and bradycardia. Monitoring is recommended if co-administration is unavoidable. NCBI Bookshelf
What is the primary antiarrhythmic mechanism of ranolazine?
Inhibition of late sodium current
Blockade of delayed rectifier potassium current
Beta-adrenergic receptor antagonism
Calcium channel blockade
Ranolazine inhibits the late phase of the sodium current (INa), reducing intracellular sodium and calcium overload in ischemic cardiac myocytes. This stabilization of the myocardial membrane can have antiarrhythmic effects, particularly in ventricular arrhythmias. It does not significantly block potassium or calcium channels at therapeutic doses. NCBI Bookshelf
Sotalol is known for blocking which receptors in addition to potassium channels?
Beta-1 and beta-2 adrenergic receptors
Alpha-1 adrenergic receptors
Muscarinic receptors
Dopamine receptors
Sotalol is a nonselective beta-blocker that antagonizes both beta-1 and beta-2 receptors, in addition to its Class III potassium channel-blocking properties. Its beta-blockade contributes to rate control, while potassium blockade prolongs action potential duration. These combined effects are unique among antiarrhythmics. NCBI Bookshelf
In atrial fibrillation with Wolff-Parkinson-White syndrome, which drug is contraindicated due to risk of accelerating conduction through the accessory pathway?
Verapamil
Digoxin
Amiodarone
Metoprolol
Verapamil (and other AV nodal blockers like digoxin) can preferentially block the AV node, encouraging conduction via the accessory pathway in WPW patients with atrial fibrillation. This can lead to rapid ventricular rates and hemodynamic instability. Procainamide is the preferred agent in this setting. Merck Manual
What is the mechanism of action of adenosine in terminating supraventricular tachycardias?
Activation of inward rectifier potassium current and inhibition of calcium current in the AV node
Beta-adrenergic blockade
Sodium channel blockade
Potassium channel blockade
Adenosine binds to A1 receptors in the AV node, activating inward rectifier potassium channels and inhibiting L-type calcium channels, which hyperpolarizes the node and transiently blocks conduction. This effect can terminate reentrant supraventricular tachycardias. The action has an ultra-short duration of seconds. NCBI Bookshelf
Genetic polymorphisms of which cytochrome P450 enzyme significantly affect the metabolism of metoprolol?
CYP2D6
CYP3A4
CYP1A2
CYP2C9
Metoprolol is primarily metabolized by CYP2D6, and genetic polymorphisms in this enzyme can lead to poor or ultra-rapid drug metabolism. This results in variability in plasma levels and therapeutic response, necessitating dose adjustments. Genetic testing may be considered in cases of unusual responses. NCBI Bookshelf
Which class of antiarrhythmics prolongs the action potential duration without significantly affecting conduction velocity?
Class III
Class IC
Class IB
Class II
Class III antiarrhythmics, such as amiodarone, sotalol, and dofetilide, primarily block potassium channels, leading to prolonged repolarization and increased action potential duration without major effects on conduction velocity. This prolongation increases refractory periods and helps terminate reentrant arrhythmias. Merck Manual
Which beta-blocker is considered safer in patients with reactive airway disease due to greater beta-1 selectivity?
Metoprolol
Propranolol
Carvedilol
Sotalol
Metoprolol is a cardioselective beta-1 blocker that has less impact on beta-2 receptors in the bronchial smooth muscle, making it relatively safer for patients with asthma or COPD. Nonselective agents like propranolol and sotalol can exacerbate bronchospasm. Selectivity decreases at higher doses. NCBI Bookshelf
Variants in the SCN5A gene, encoding the cardiac sodium channel, primarily affect the response to which antiarrhythmic drug?
Flecainide
Sotalol
Amiodarone
Verapamil
SCN5A gene variants can alter sodium channel structure and function, impacting the efficacy and safety of sodium channel blockers like flecainide (Class IC). These polymorphisms may lead to variable drug responses, including proarrhythmic risk. Genetic screening can guide personalized therapy. NCBI PMC
Which antiarrhythmic drug demonstrates reverse use-dependence, with greater action potential prolongation at slower heart rates?
Sotalol
Lidocaine
Esmolol
Flecainide
Reverse use-dependence refers to increased drug effect at slower heart rates and is characteristic of many Class III agents, including sotalol. At slow rates, potassium channel blockade is enhanced, prolonging repolarization. This property can increase the risk of torsades de pointes at bradycardia. NCBI Bookshelf
Ivabradine, though not a traditional antiarrhythmic, slows heart rate by inhibiting which pacemaker current?
Funny (If) current
L-type calcium current
Delayed rectifier potassium current
Fast sodium current
Ivabradine selectively inhibits the funny current (If) in the sinoatrial node by blocking HCN channels, reducing spontaneous diastolic depolarization and heart rate. It has no direct effects on contractility or conduction velocity. It is used in heart failure and angina rather than classic arrhythmia therapy. NCBI Bookshelf
Which beta-blocker is preferred as first-line therapy for catecholaminergic polymorphic ventricular tachycardia (CPVT)?
Nadolol
Metoprolol
Propranolol
Atenolol
Nadolol, a nonselective beta-blocker with a long half-life and no intrinsic sympathomimetic activity, is the preferred first-line therapy for CPVT. It blunts adrenergic stimulation that precipitates arrhythmias in this genetic disorder. Propranolol is an alternative but less favored due to shorter duration. NCBI Bookshelf
In patients with Brugada syndrome, which class of antiarrhythmic drugs is contraindicated because it can unmask ECG changes and provoke arrhythmias?
Class IC
Class IA
Class III
Class IV
Class IC agents, such as flecainide and propafenone, can exacerbate the ECG alterations of Brugada syndrome by further reducing sodium current, which may provoke ventricular arrhythmias. These drugs are contraindicated in Brugada patients. Alternative management includes quinidine and ICD placement. NCBI PMC
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Study Outcomes

  1. Understand antiarrhythmic drug classes -

    Define the four main Vaughan-Williams classes and describe how each class alters cardiac electrophysiology to manage arrhythmias.

  2. Identify mechanisms of action -

    Explain how sodium, beta, potassium, and calcium channel blockers influence cardiac rhythm at the molecular level.

  3. Analyze treatment scenarios -

    Apply pharmacotherapy principles to select the most appropriate antiarrhythmic agent for common clinical arrhythmia presentations.

  4. Evaluate efficacy and safety -

    Assess the therapeutic benefits of antiarrhythmic drugs against their potential side effects and contraindications in patient-specific contexts.

  5. Compare drug profiles -

    Distinguish between key antiarrhythmic medications based on onset of action, metabolism, dosing, and monitoring requirements.

  6. Reinforce knowledge through feedback -

    Use quiz results to identify knowledge gaps and strengthen mastery of heart rhythm pharmacotherapy.

Cheat Sheet

  1. Vaughan Williams Classification of Antiarrhythmics -

    The Vaughan Williams system divides antiarrhythmic drugs into four main classes (I - IV) based on their primary ion channel or receptor targets. Remember "No Bad Knocks Causing Problems" for Na❺ (I), β-blockers (II), K❺ (III), Ca²❺ (IV). This framework is essential when you tackle an arrhythmia test online to match mechanism with clinical use.

  2. Class I Subclasses: IA, IB, IC -

    Class I agents block fast Na❺ channels but differ in kinetics: IA (e.g., quinidine) moderately slows conduction and prolongs repolarization, IB (lidocaine) rapidly dissociates and shortens repolarization, and IC (flecainide) strongly depresses Phase 0 without affecting repolarization. A handy mnemonic is "Double, Big, Chunky" corresponding to IA, IB, IC for conduction effect size. Mastering these differences boosts your score on antiarrhythmic drugs test questions.

  3. Cardiac Action Potential Phases and Drug Targets -

    Understanding the five phases (0 - 4) of the ventricular action potential helps you see where each drug acts: Class III prolongs Phase 3 repolarization by blocking K❺ channels, lengthening the QT interval. Recall the formula QTc = QT/√RR for rate correction when evaluating proarrhythmic risk. This concept often appears in pharmacotherapy of arrhythmia quizzes for drug mechanism questions.

  4. Proarrhythmia and QT Monitoring -

    Some antiarrhythmics, especially Class III (e.g., sotalol, dofetilide), can induce torsades de pointes by excessively prolonging QTc. Knowing to calculate QTc and monitor electrolytes (K❺, Mg²❺) is vital for safe prescribing. When you take a heart rhythm quiz, linking side-effect profiles to ECG changes shows true mastery.

  5. Clinical Selection by Arrhythmia Type -

    Choosing the right agent depends on the arrhythmia: beta-blockers or calcium channel blockers for rate control in atrial fibrillation, adenosine for AV nodal reentrant tachycardia, and amiodarone for life-threatening ventricular tachycardia. Use the mnemonic "ABCD" (Adenosine, Beta-blockers, Calcium-blockers, Defibrillation) to recall initial treatments. This strategy makes your performance in an arrhythmia quiz stand out.

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