antiarytmikot

Antiarytmika are medications used to treat abnormal heart rhythms by modifying the electrical activity of the heart. They can prevent, slow down, or convert tachyarrhythmias and are commonly used in conditions such as atrial fibrillation, atrial flutter, and ventricular arrhythmias. Drugs are often grouped by the Vaughan Williams classification, which groups agents by their primary effect on cardiac ion channels and conduction. Some antiarytmics do not fit neatly into this system and are used in specific situations.

Class I drugs are sodium channel blockers that slow impulse conduction. They are subdivided into IA (moderate slowing, e.g., quinidine, procainamide), IB (fast recovery, e.g., lidocaine), and IC (strong slowing, e.g., flecainide, propafenone). Class II consists of beta-blockers (e.g., metoprolol, propranolol) that reduce sympathetic stimulation. Class III agents prolong repolarization and the QT interval (e.g., amiodarone, sotalol, dofetilide, ibutilide) and are effective against various tachycardias but carry a risk of proarrhythmia. Class IV comprises non-dihydropyridine calcium channel blockers (e.g., verapamil, diltiazem) that slow AV nodal conduction and are mainly used for rate control in supraventricular tachycardias.

Adverse effects and safety are important considerations. Proarrhythmia, particularly torsades de pointes with QT prolongation, is a risk with several agents. Amiodarone, while effective against many arrhythmias, has long-lasting organ toxicity potential (thyroid, liver, lungs, skin). Drug interactions and electrolyte disturbances influence efficacy and safety, necessitating careful monitoring of rhythm, ECG intervals, electrolytes, and organ function.

Administration and use depend on the specific rhythm, patient comorbidity, and setting, with treatment often guided by electrophysiology specialists.