Quiz on antiarrhythmic drugs: class 3

✓ Passing Score: 50%

📝 Questions: 10

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Question 1 of 10

A 50-year-old male with a history of Wolff-Parkinson-White (WPW) syndrome and supraventricular tachycardia (SVT) is managed with oral amiodarone for frequent episodes. He experiences a breakthrough episode of SVT and presents to the ED. His ECG shows a narrow complex tachycardia with a regular rhythm. Which of the following mechanisms explains amiodarone\'s effectiveness in treating SVT in WPW syndrome? *

Blockade of potassium channels, prolonging repolarization. Slowing of conduction through the His-Purkinje system. Blockade of sodium channels in the AV node. Prolongation of the refractory period in the accessory pathway. Inhibition of the sympathetic nervous system.

A 45-year-old female with a history of hypertrophic cardiomyopathy (HCM) and recurrent ventricular arrhythmias is being considered for antiarrhythmic therapy. She has a normal ejection fraction but experiences frequent symptomatic episodes of ventricular tachycardia. Which of the following Class III antiarrhythmic agents is generally *contraindicated* in patients with HCM due to an increased risk of proarrhythmia? *

Sotalol Amiodarone Dronedarone Dofetilide Ibutilide

A 75-year-old female with persistent atrial fibrillation is switched from warfarin to apixaban due to concerns about bleeding. She has a history of stable angina and is on amiodarone for rhythm control. Which of the following is the *most* likely consequence of this medication change? *

Potential for apixaban to increase the metabolism of amiodarone. Increased risk of stroke due to decreased anticoagulant effect. Potential for amiodarone to increase the clearance of apixaban. No significant interaction anticipated between amiodarone and apixaban. Increased risk of bleeding due to amiodarone\'s interaction with apixaban.

A 60-year-old female with a history of Graves\' disease and persistent atrial fibrillation is initiated on amiodarone for rhythm control. She has no other significant cardiac history. After 3 months of therapy, she reports increasing fatigue, unintentional weight loss, and feeling cold. Laboratory tests reveal a suppressed TSH (<0.01 mIU/L) and elevated free T4. Which of the following is the *most* likely adverse effect of amiodarone in this patient? *

Hepatotoxicity Pulmonary fibrosis Hypothyroidism Hyperthyroidism Corneal microdeposits

A 70-year-old male with a history of dilated cardiomyopathy and sustained ventricular tachycardia is admitted for electrical storm. He is currently on amiodarone, but his VT persists despite aggressive management. He is also receiving amlodipine for hypertension. His physician considers adding a beta-blocker. Which of the following statements regarding the combination of amiodarone and beta-blockers is accurate? *

Beta-blockers are contraindicated in patients receiving amiodarone. The combination generally leads to additive negative inotropic effects, potentially worsening heart failure. The combination increases the risk of torsades de pointes. Beta-blockers can counteract the bradycardic effects of amiodarone. The combination is rarely used due to significant pharmacokinetic interactions.

A 65-year-old male with symptomatic paroxysmal atrial fibrillation is initiated on dronedarone for rhythm control. He has a history of moderate heart failure (NYHA class II) but no history of severe heart failure or recent decompensation. He is also on a moderate dose of simvastatin. Which of the following is a crucial precaution or contraindication for dronedarone use in this patient? *

Concurrent use of strong CYP3A4 inhibitors. History of severe heart failure (NYHA class III-IV) or recent decompensation. All of the above. Significant QT prolongation on baseline ECG. Concomitant use with warfarin.

A 55-year-old male with a history of recurrent ventricular tachycardia (VT) after a myocardial infarction is being considered for antiarrhythmic therapy. He has a moderate degree of renal impairment (CrCl 45 mL/min). His baseline QT interval is normal. Which of the following Class III antiarrhythmic agents would require dose adjustment or careful consideration due to his renal function? *

Sotalol Dronedarone Bretylium Amiodarone Dofetilide

A 72-year-old female with a history of ischemic cardiomyopathy and permanent atrial fibrillation is managed on warfarin for stroke prevention. She develops recurrent symptomatic supraventricular tachycardia requiring intervention. Her cardiologist decides to initiate amiodarone for rhythm control. Which of the following is the *most* important drug interaction to monitor for when initiating amiodarone in this patient? *

Increased risk of hyperkalemia with her current diuretic therapy. Inhibition of amiodarone metabolism by her statin. Additive QT prolongation with her beta-blocker therapy. Decreased absorption of amiodarone due to her proton pump inhibitor. Potentiation of warfarin\'s anticoagulant effect.

A 68-year-old male with a history of heart failure with reduced ejection fraction (HFrEF) and persistent atrial fibrillation presents to the emergency department with palpitations and dyspnea. His ECG shows rapid ventricular response at 150 bpm. He is hemodynamically stable. He is currently taking lisinopril and furosemide. Which of the following Class III antiarrhythmic agents would be the *most* appropriate choice for rate and rhythm control in this patient, considering his underlying condition? *

Dofetilide Sotalol Ibutilide Vernakalant Amiodarone

A 58-year-old male with a history of recurrent ventricular tachycardia (VT) post-myocardial infarction is on amiodarone. He presents with new-onset visual disturbances, including blurred vision and halos around lights. His ophthalmologist notes diffuse corneal microdeposits. Which of the following is the *most* accurate statement regarding amiodarone-induced corneal microdeposits? *

They are a rare adverse effect, only seen with very high doses of amiodarone. They are a common, usually benign, side effect that may resolve upon dose reduction or discontinuation. They are typically asymptomatic and do not affect visual acuity. They are a sign of severe amiodarone toxicity and require immediate hospitalization. They are permanent and irreversible, requiring discontinuation of amiodarone.