To the Editor— Propranolol, a β-adrenoreceptor blocker, prevents arrhythmias also by its sodium channel blocking effect

Abstract

Calvillo et al1 report a ventricular antiarrhythmic effect of high-dose propranolol in a model of long QT syndrome 3 (LQT3). They interpret their findings as support for the therapeutic efficacy of β-adrenoceptor blockers in LQT3. It seems important to put their findings in context: Propranolol is not only a β-adrenoceptor blocker but also a sodium channel blocker, as authors briefly mention.2 Propafenone is another example of a combined sodium channel and β-adrenoceptor blocker.