Whether oral
anticoagulants,
vitamin K antagonists (VKAs), and nonvitamin K oral
anticoagulant (NOACs) frequently prescribed to
atrial fibrillation (AF) patients, do themselves have a pro- or
anti-arrhythmic effect have never been addressed. Transmembrane action potentials were recorded in an acute rabbit model of superfused pulmonary veins (PVs) sleeves preparations using standard
microelectrode technique.
Fluindione 10 μm (n = 6) increased the AP (action potential) duration (APD), induced a significantly Vmax depression (from 95 ± 14 to 53 ± 5 V/s, P < 0.05), and 2 : 1 blocks during rapid atrial pacing thus evoking class I
anti-arrhythmic properties, and prevented spontaneous trigger APs.
Apixaban 10 μm (n = 6) increased the APD, significantly prolonged the effective refractory period (from 56.3 ± 4.2 to 72.0 ± 8.6 ms, P < 0.05), and prevented triggered APs occurrence.
Fluindione and
apixaban effects were suppressed with the addition of the
protease-activated receptors 1 (PAR 1) agonist
SFLLR-NH2 .
Warfarin 10 μm (n = 6) significantly abbreviated the early refractory period (from 56.3 ± 4.2 to 45.0 ± 2.2 ms, P < 0.05) and increased triggered APs occurrence that were successfully prevented by
nifedipine but not by the addition of the
protease-activated receptors 1 agonist
SFLLR-NH2 . In this acute rabbit PVs model, VKAs and NOACs, at physiological concentrations, exhibited very different pharmacological properties that influence PVs electrophysiology, implying PAR1, with
fluindione and
apixaban which exhibited more
anti-arrhythmic properties, whereas
warfarin exhibited more pro-arrhythmic properties.