Cardiac Arrhythmia Management Flashcards
7 cards from real CMC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Cardiac Arrhythmia Management flashcards as text
A patient develops sudden onset palpitations and an ECG shows a regular wide-complex tachycardia at 220 bpm with a delta wave. WPW syndrome is suspected. Which drug is contraindicated in this setting?
Answer: IV adenosine
Adenosine is contraindicated in pre-excited atrial fibrillation with WPW because blocking the AV node can preferentially route conduction through the accessory pathway, potentially accelerating ventricular rate and precipitating ventricular fibrillation.
Which finding confirms a successful catheter ablation of an accessory pathway in a patient with WPW syndrome?
Answer: Disappearance of the delta wave and normalization of the PR interval
Successful ablation of the accessory pathway eliminates pre-excitation, resulting in disappearance of the delta wave and normalization of the PR interval as conduction now occurs exclusively through the AV node.
A patient in the cardiac ICU develops ventricular fibrillation. After defibrillation and ROSC, which medication should be initiated to reduce recurrent VF?
Answer: IV amiodarone infusion
IV amiodarone is the standard pharmacologic agent used post-resuscitation to suppress recurrent ventricular fibrillation and maintain electrical stability while underlying causes are addressed.
What is the significance of a prolonged QTc interval greater than 500 ms in a cardiac patient?
Answer: It markedly increases the risk of torsades de pointes
A QTc greater than 500 ms represents significant prolongation of ventricular repolarization, substantially increasing the risk of torsades de pointes, a potentially fatal polymorphic ventricular tachycardia.
A patient with sick sinus syndrome presents with symptomatic bradycardia alternating with episodes of supraventricular tachycardia. Which management approach best addresses both components of this condition?
Answer: Permanent pacemaker implantation with rate-controlling medications for tachyarrhythmia
Tachy-brady syndrome (sick sinus syndrome) requires a permanent pacemaker to protect against symptomatic bradycardia while allowing safe use of rate-controlling or antiarrhythmic drugs to manage the tachyarrhythmic component.
Which ECG feature differentiates Mobitz type II second-degree AV block from Mobitz type I?
Answer: Constant PR interval before a sudden dropped QRS in Mobitz II
Mobitz type II is characterized by a constant, unchanging PR interval followed by a sudden failure of a P wave to conduct (dropped QRS), without the progressive PR lengthening seen in Wenckebach.
Which class of antiarrhythmic drugs is most appropriate for long-term rate control in a patient with persistent atrial fibrillation and reduced left ventricular ejection fraction (EF 35%)?
Answer: Beta-blockers (carvedilol or metoprolol succinate)
Beta-blockers such as carvedilol and metoprolol succinate are the preferred agents for rate control in atrial fibrillation with reduced EF because they also improve survival in heart failure, whereas non-dihydropyridine CCBs are contraindicated and Class IC/IA agents carry increased arrhythmia risk in structural heart disease.