Fig. 3
From: Atrial fibrillation and its arrhythmogenesis associated with insulin resistance
Effects of action potential duration (APD), calcium transient duration (CaTD), and conduction velocity (CV) of right atrial appendages (RAAs) of high-fat (HFa) and high-fructose/cholesterol (HFr) diet-fed rats at different pacing cycle lengths (PCLs). a Representative optical membrane voltage (Vm) and calcium traces, action potential duration at 80% repolarization (APD80), and CaTD at 80% repolarization (CaTD80) maps of RAAs in control, HFr, and HFa diet-fed rats at different PCLs. Prolongation of overall CaTD80 and appearance of calcium alternans of RAAs were noted in HFr and HFa diet-fed rats as compared with control rats. The pacing site (asterisk) was located at the upper edge of the RAA. b Mean value of APD80 versus PCL for control (n = 5), HFr (n = 5), and HFa diet-fed rats (n = 5). No difference in average APD80 was observed between control, HFr, and HFa diet-fed rats. The mean values of CaTD80 versus PCL for control, HFr, and HFa diet-fed rats are shown. The RAAs of HFr and HFa diet-fed rats had a larger average CaTD80 than did those of the control rats at each PCL. No differences in the mean coefficient of variation (COV) of APD80 and CaTD80 were observed between control, HFr, and HFa diet-fed rats. c Isochronal maps of the representative control, HFr, and HFa diet-fed rats. The pacing site (asterisk) was located at the upper edge of the RAA. d Summary of CV measured from the pacing site to the RAA–right atrial junction in control (n = 5), HFr (n = 5), and HFa diet-fed rats (n = 5). The RAAs of HFr and HFa diet-fed rats had a slower CV than did those of control rats at short PCLs of 80 and 100 ms. Two-way repeated measures ANOVA models followed by post hoc Bonferroni test were applied with factors including APD80, COV of APD80 and CV versus PCL. *P < 0.05 for HFr versus control. +P < 0.05 for HFa versus control. Each value represents the mean ± SE of five rats