PLN and atrial fibrillation: In this study, it is noteworthy that LVDCCa1c expression levels were significantly downregulated, however, intracellular Ca2+ handling proteins generally showed an up-regulation tendency during ageing; moreover, the expression levels of LVDCCa1c and intracellular Ca2+ handling proteins except PLN were are highly downregulated in the adult and aged groups in AF, more specifically in the latter with AF.