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. 2020 Sep 4;319(4):H893–H905. doi: 10.1152/ajpheart.00379.2020

Fig. 3.

Fig. 3.

Altered sodium channel function and heart rate properties with age. A: ECGs recorded in genetically engineered S571E male mice. Traces obtained in mice at 3 and 24 mo of age are shown. B: data for average RR interval duration in S571E male mice at different age intervals. SDRR, standard deviation (SD) of RR intervals; CVRR, coefficient of variation of RR intervals; RMSSD, square root of the mean of the squared differences between adjacent RR. C: data for time-domain parameters of heart rate variability (HRV). D: data for frequency-domain parameters of HRV; m, months. E: frequency bands normalized by total power. F: data for low frequency-to-high frequency (LF/HF) ratio. G: Poincaré plots obtained from ECGs recorded from male S571E mice at 6 and 21 mo of age. RRn and RRn+1 axes span from 75 to 95 ms. H: data for nonlinear indexes obtained from Poincaré plots from S571E mice at different ages. Quantitative data shown in B–D and F were obtained from male S571E mice at ~4 mo (n = 51), ~12 mo (n = 14), ~18 mo (n = 18), and ~24 mo (n = 14) of age. Data are presented as medians and interquartile ranges. *P < 0.05 vs. ~4 m; **P < 0.05 vs. ~12 mo.