Cardiac alternans were induced by increasing the pacing frequency. It was found that action potential duration (APD) alternans increased 10 minutes after reperfusion, while pretreatment with GSK219 or TRPV4 gene knockout did not affect ischemia-reperfusion (IR)-induced susceptibility to APD alternans. Regarding calcium transient (CaT) alternans, distinct manifestations were observed at different pacing frequencies: IR increased CaT alternans and reduced the alternans threshold, whereas pretreatment with GSK219 or TRPV4 gene knockout inhibited IR-induced CaT alternans and decreased the incidence of discordant alternans. These results indicate that inhibiting TRPV4 can suppress CaT alternans but not APD alternans.

(A-C) Example of CaT maps (upper panel) at progressively faster pacing rates and CaT traces from the location indicated with a box in the upper maps (lower panel). (D) Calculation diagram of CaT alternans. (E) Quantification of CaT alternans at progressively faster pacing rates. (F) Incidence of discordant alternans during baseline and reperfusion.

Heart Rhythm (IF 5.6)

DOI: 10.1016/j.hrthm.2025.04.006