Figure 3.

Frequency-dependent effects of XEN-D0103 in right atrial trabeculae from patients in sinus rhythm (SR). Effects on effective refractory period (ERP), action potential duration at 90% repolarization (APD₉₀), and plateau potential (defined as the mean absolute membrane potential [in mV] in the time window between 20% and 30% of APD₉₀ [PLT₂₀]) depicted as the difference between predrug control and in the presence of the drug (delta values). Note that in SR, none of the preparations followed stimulation at 5 Hz in the presence of XEN-D0103. Separate time-matched control (TMC) experiments without drug application are shown on the right side. Delta values in the presence of the drug were compared with the corresponding TMC data at each frequency using an unpaired Student t test. The results of this comparison are shown as ^##P < .01 and ^###P < .0001. Delta values at each frequency (1–3 Hz) in the presence of the drug were compared in a group to determine frequency-dependent drug effects using a repeated-measures analysis of variance (results shown as a line, comparing 1–3 Hz) with a Bonferroni posttest (results shown in the inset). Failure to capture action potentials in all preparations at 5 Hz precluded comparison of this group using a repeated-measures test.