Скачать или смотреть Antiarrhythmic drugs; medications used to prevent or treat abnormal heart rhythms arrhythmias

What Are Antiarrhythmic Drugs?
Definition: Medications used to prevent, control, or treat abnormal heart rhythms (arrhythmias).

Mechanism: They act on cardiac ion channels or autonomic pathways to restore normal rhythm and conduction.

Uses: Atrial fibrillation, atrial flutter, supraventricular tachycardia, ventricular tachycardia, and ventricular fibrillation.

Vaughan-Williams Classification of Antiarrhythmic Drugs
Class Examples Mechanism of Action Clinical Use
Class I (Na⁺ channel blockers) Quinidine, Procainamide, Lidocaine, Flecainide Block sodium channels → slow conduction Atrial and ventricular arrhythmias
Class II (β-blockers) Propranolol, Metoprolol, Esmolol Reduce sympathetic tone → decrease automaticity Supraventricular arrhythmias, rate control in AF
Class III (K⁺ channel blockers) Amiodarone, Sotalol, Dofetilide Prolong repolarization → increase refractory period Atrial fibrillation, ventricular arrhythmias
Class IV (Ca²⁺ channel blockers) Verapamil, Diltiazem Slow conduction in SA/AV nodes Supraventricular tachycardia, rate control in AF
Class V (Miscellaneous) Adenosine, Digoxin Adenosine: transient AV block; Digoxin: increases vagal tone Adenosine: acute SVT; Digoxin: rate control in AF (esp. with heart failure)
Key Points
Amiodarone: Broad-spectrum, highly effective but with significant long-term toxicities (thyroid, pulmonary, hepatic).

β-blockers and Ca²⁺ channel blockers: Often used for rate control in atrial fibrillation.

Adenosine: Very short half-life, used acutely for paroxysmal supraventricular tachycardia (PSVT).

Digoxin: Useful in AF with heart failure, but narrow therapeutic index

#Arrythmia