The development of a new antiarrhythmic drug involves many people with disparate skills. The organic chemist who makes it is guided not only by the structure-action relations of previous compounds, but by anticipation of a requirement for a particular type of action. In fact several of the best-known antiarrhythmics, including lidocaine, mexiletine, amiodarone and verapamil, were originally synthesized for other purposes. Physicians have to determine whether the new drug works, and pharma- cologists how it works. For some years I have believed that there was room for a work which could be...