Hydrogen sulphide increases pulmonary veins and atrial arrhythmogenesis with activation of protein kinase C

Hydrogen sulphide (H2S), one of the most common toxic air pollutants, is an important aetiology of atrial fibrillation (AF). Pulmonary veins (PVs) and left atrium (LA) are the most important AF trigger and substrate. We investigated whether H2S may modulate the arrhythmogenesis of PVs and atria. Conventional microelectrodes and whole-cell patch clamp were performed in rabbit PV, sinoatrial node (SAN) or atrial cardiomyocytes before and after the perfusion of NaHS with or without chelerythrine (a selective PKC inhibitor), rottlerin (a specific PKC inhibitor) or KB-R7943 (a NCX inhibitor). NaHS reduced spontaneous beating rates, but increased the occurrences of delayed afterdepolarizations and burst firing in PVs and SANs. NaHS (100 mol/L) increased I-KATP and I-NCX in PV and LA cardiomyocytes, which were attenuated by chelerythrine (3 mol/L). Chelerythrine, rottlerin (10 mol/L) or KB-R7943 (10 mol/L) attenuated the arrhythmogenic effects of NaHS on PVs or SANs. NaHS shortened the action potential duration in LA, but not in right atrium or in the presence of chelerythrine. NaHS increased PKC activity, but did not translocate PKC isoforms , epsilon to membrane in LA. In conclusion, through protein kinase C signalling, H2S increases PV and atrial arrhythmogenesis, which may contribute to air pollution-induced AF.