Key result
Isoproterenol fully reversed sematilide-induced APD90 prolongation but only partially attenuated amiodarone-induced prolongation, which remained 6% above baseline (P=0.005).
Why the study?
Does beta-adrenergic stimulation with isoproterenol differentially affect the electrophysiologic actions of sematilide and amiodarone in humans?
Does beta-adrenergic stimulation with isoproterenol differentially affect the electrophysiologic actions of sematilide and amiodarone in humans?
p-value: p=0.005
Beta-adrenergic stimulation fully reverses the electrophysiologic effects of the pure class III agent sematilide but only partially attenuates the effects of amiodarone, which may explain differences in their clinical efficacy for arrhythmia protection.
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Sympathetic stimulation may blunt pure class III effects more than amiodarone; leaves open clinical relevance for arrhythmia suppression.
Sager et al. (1994) studied Ventricular arrhythmias (n=33). Isoproterenol vs. Drug-free baseline and steady-state antiarrhythmic dosing before isoproterenol was evaluated on Ventricular action potential duration at 90% repolarization (APD90) (p=0.005). Isoproterenol fully reversed sematilide-induced APD90 prolongation but only partially attenuated amiodarone-induced prolongation, which remained 6% above baseline (P=0.005).
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