Adverse cardiovascular effects of anti-arrhythmia drugs. Part I: Proarrhythmic effects

Antiarrhythmic drugs are able to save patients from emergency dysrhythmic situations or to avoid symptomatic disorders when used in a prophylactic goal. However they can also induce adverse effects. Cardiovascular adverse effects, and especially proarrhythmic effects, are the most dreaded. Analysis of the underlying mechanisms of the onset and perpetuation of sustained arrhythmias could lead to a better understanding of causes of proarrhythmic effects and thus to a limitation of their occurrence. Antiarrhythmic drugs can modulate the three principal factors which are involved in the onset of arrhythmias: individual predisposing factors, trigger mechanisms and environmental factors. This multiparameter modulation will conduct either to suppress the arrhythmic disorders (antiarrhythmic effect) or to impair it (proarrhythmic effect). According to the numerous factors which take part in the onset and perpetuation of arrhythmia, incidence of proarrhythmic effect of antiarrhythmic drugs is very difficult to evaluate.