Antiarytmien

Antiarytmien are medicines used to treat abnormal heart rhythms by altering the heart's electrical activity. They may be used to suppress both atrial and ventricular arrhythmias and to restore or maintain normal rhythm (rhythm control) or to slow the heart rate (rate control). Selection depends on the rhythm type, underlying heart disease, and other medical factors.

They are commonly classified by the Vaughan Williams system into four classes: Class I sodium channel blockers (Ia: quinidine, procainamide, disopyramide; Ib: lidocaine, mexiletine; Ic: flecainide, propafenone); Class II beta-blockers (metoprolol, atenolol, propranolol); Class III potassium channel blockers prolonging repolarization (amiodarone, sotalol, dofetilide, ibutilide); Class IV calcium channel blockers (verapamil, diltiazem). Some drugs have multiple actions or do not fit neatly (e.g., amiodarone).

Mechanisms include slowed conduction, prolonged refractoriness, suppression of ectopic activity, and reduced sympathetic drive. Indications depend on rhythm type; atrial fibrillation or flutter and ventricular tachycardia are common targets. Some agents are preferred or avoided in structural heart disease or heart failure (e.g., flecainide avoided with ischemic/structural disease; amiodarone often used in heart failure).

Risks include proarrhythmia such as torsades de pointes, hypotension, bradycardia, and conduction block, plus non-cardiac toxicities (amiodarone long-term effects). Monitoring is essential: ECG for QT interval, rhythm, electrolytes, renal and hepatic function, and drug interactions. Dosing is individualized and often requires specialist oversight.