4 Antiarrhythmic Medications Free Online FlashCards

What is the main action of class I antiarrhythmics?

Class I drugs block fast sodium channels. Examples include procainamide (IA), lidocaine (IB), and flecainide and propafenone (IC).

How do class II antiarrhythmics affect the heart?

Class II drugs block beta-adrenergic effects, slowing heart rate and AV-node conduction. Monitor for bradycardia and hypotension.

What is the main action and key risk of class III antiarrhythmics?

Class III drugs prolong repolarization, mainly through potassium-channel effects. Some prolong the QT interval and can cause torsades de pointes.

How do class IV antiarrhythmics act?

Class IV drugs block L-type calcium channels in the AV node, slowing AV-node conduction. Monitor for bradycardia and hypotension.

What ECG interval can class IA drugs prolong?

Class IA drugs, such as procainamide, can prolong the QT interval.

When are class IC drugs generally avoided?

Class IC drugs such as flecainide and propafenone are generally avoided after myocardial infarction or with significant structural heart disease because of proarrhythmic risk.

What should be monitored with dofetilide or sotalol?

Dofetilide and sotalol require careful monitoring of QT, electrolytes, and kidney function because safety and arrhythmia risk depend on these factors.

What should guide antiarrhythmic drug choice?

Choose treatment based on the identified rhythm and the patient’s stability, rather than trying to suppress every irregularity.

What are treatment options for stable AF with ventricular pre-excitation?

Clinician-directed options include intravenous procainamide or ibutilide, or electrical cardioversion.

Why may flecainide be paired with an AV-nodal blocker?

Flecainide can organize AF into atrial flutter. Pairing it with an AV-nodal blocker reduces the risk of rapid 1:1 conduction to the ventricles.

Which major toxicities should be monitored with long-term amiodarone?

Important long-term risks include pulmonary, thyroid, and hepatic toxicity. New cough, shortness of breath, jaundice, or possible thyroid symptoms warrant prompt clinical assessment.

What is the priority when tachycardia causes hemodynamic instability?

Instability such as hypotension or acute confusion requires urgent action. Electrical cardioversion is used when indicated by the rhythm; follow emergency protocols.