Pharmacogenetics and Cardiac Ion Channels
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.