ABSTRACT

The use of drugs to treat cardiac arrhythmias is characterized by highly variable efficacy and serious toxicity. Both of these are difficult to predict in an individual patient. Studies of the mechanisms underlying this variability and unpredictability in drug action have been important platforms for defining the role of genetics in drug action and have also pointed to general mechanisms in the initiation and maintenance of abnormal cardiac rhythms. In practical terms, the past decade has seen a decline in the use of antiarrhythmic drugs, in part because of their unpredictable efficacy and toxicity. As well, ‘‘non-pharmacologic’’ techniques, including ablation of abnormal tissues underlying arrhythmias and implantable defibrillators, have matured and are increasingly used.