antiarrytmische

Antiarrhythmics, also referred to in German as antiarrytmische Mittel, are drugs used to treat abnormal heart rhythms by modifying the electrical activity of the heart. They are commonly categorized by the Vaughan Williams system into four main classes, with some agents having multiple mechanisms of action.

Class I agents are sodium channel blockers that slow conduction and alter the action potential. They are subdivided into IA (quinidine, procainamide), IB (lidocaine, mexiletine), and IC (flecainide, propafenone). Class II comprises beta-adrenergic blockers (metoprolol, propranolol, esmolol), which reduce sympathetic stimulation and can slow the ventricular rate. Class III agents prolong repolarization by blocking potassium channels; examples include amiodarone, sotalol, dofetilide, and ibutilide. Class IV includes nondihydropyridine calcium channel blockers (verapamil, diltiazem) that slow AV node conduction and decrease heart rate.

Amiodarone is a widely used antiarrhythmic with properties of several classes, and other agents with similar utility include dofetilide, ibutilide, and vernakalant (availability varies by region). The choice of drug depends on the specific arrhythmia, presence of structural heart disease, and patient comorbidities.

Indications include atrial fibrillation and atrial flutter, other supraventricular tachycardias, ventricular tachycardia, and maintenance of sinus rhythm after rhythm conversion. Antiarrhythmics may be used for rhythm control or, in some cases, rate control, depending on the clinical scenario and guideline recommendations.

Safety and monitoring are essential. These drugs can cause proarrhythmia, including torsades de pointes, especially with QT prolongation, electrolyte disturbances, or structural heart disease. Adverse effects vary by drug (for example, pulmonary fibrosis with long-term amiodarone; bradycardia with beta-blockers and calcium channel blockers). Regular ECG monitoring, electrolyte management, and awareness of drug interactions are important components of therapy.