Are antiarrhythmic drugs safe?

The indications for antiarrhythmic therapy are far from clearly defined and the choice of treatment is usually based on empiric strategies. Antiarrhythmic agents can have serious side effects. Systemic adverse effects are usually use-related and reversible with withdrawal of the drug. Impairment of left ventricular function is considerable in patients with heart failure. The most important, life-threatening side effect of antiarrhythmic drugs is their proarrhythmic tendency which gives rise to certain concern about their clinical use. Aggravation of arrhythmia often occurs without symptoms, goes unrecognized by the patient, and is exposed only by monitoring, exercise testing, or invasive electrophysiological testing. Patient monitoring with electrolyte measurement, Holter recording, and electrophysiological reassessment can reveal or reduce the proarrhythmic risk but cannot eliminate the problem completely. The institution of antiarrhythmic therapy should be considered in highly symptomatic or life-threatening arrhythmias after careful consideration of the benefit-risk ratio.