Increased atrial effectiveness of flecainide conferred by altered biophysical properties of sodium channels.

ABSTRACT: Atrial fibrillation (AF) affects over 1% of the population and is a leading cause of stroke and heart failure in the elderly. A feared side effect of sodium channel blocker therapy, ventricular pro-arrhythmia, appears to be relatively rare in patients with AF. The biophysical reasons for this relative safety of sodium blockers are not known. Our data demonstrates intrinsic differences between atrial and ventricular cardiac voltage-gated sodium currents (I_Na), leading to reduced maximum upstroke velocity of action potential and slower conduction, in left atria compared to ventricle. Reduced atrial I_Na is only detected at physiological membrane potentials and is driven by alterations in sodium channel biophysical properties and not by Na_V1.5 protein expressio

SUBMITTER: O' Brien S 

PROVIDER: S-EPMC7616974 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature