This review summarizes the electrophysiologic and electrocardiographic properties of Class IA and IB antiarrhythmic drugs, noting their specific effects on action potentials and QT intervals.
Reminds clinicians of QTc monitoring needs with Class IA agents; confirms classic electrophysiologic profiles without new trial data.
Class 1A agents share the electrophysiologic property of slmuing of V max of phase 0 of the action potential and moderate prolongation of the action potential duration and refractoriness. Their electrocardiographic effect in therapeutic doses is to prolong the QT c . interval due to prolongation of the JT c interval. The PR and QRS intervals are not prolonged in therapeutic doses. This group of agents contains the standard antiarrhythmic agents released prior to 1984. The older drugs in this group wilt be reviewed only briefly in this report. Their effect on suppression of ventricular ectopic depolarizations will be reviewed for comparison with the newer agents.
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David M. Salerno (1990) studied this question.
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