查看文章

Background: Alternans, the periodic beat-to-beat alternation in electrical and calcium signaling of a cardiac myocyte stimulated at a fixed frequency is well documented to be proarrhythmic. Nonetheless, the involvement of alternans in the processes promoting paroxysmal atrial fibrillation (pAF) is unknown. As such, we set out to ascertain if alternans contribute to the arrhythmogenic mechanisms in pAF.

Methods: Simultaneous action potentials (patch-clamp) and [Ca²⁺]_i (Fluo3) were recorded in right atrial myocytes obtained from patients with sinus rhythm (Ctl; n=16) and pAF (n=8). AP and CaT alternans were acquired and analyzed using a custom-written software.

Results: AP duration was similar between pAF and Ctl groups over different pacing frequencies, exempting electrical remodeling in pAF. A higher incidence of CaT alternans (46% vs 18%; P=0.08) and AP alternans (82% vs 52%; P<0.05) was observed in …