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. Author manuscript; available in PMC: 2024 Jan 1.
Published in final edited form as: Heart Rhythm. 2022 Nov 15;20(1):76–86. doi: 10.1016/j.hrthm.2022.09.021

Fig. 3. Heart rate variability (HRV).

Fig. 3.

A-E. HRV analyzed by time domain method. NN interval, the normal-to-normal RR interval; SDNN, the standard deviation of the NN intervals; RMSSD, the root mean square of successive differences between normal heartbeats; NN9, the number of pairs of successive NN intervals that differ by more than 9 ms; pNN9, the proportion of NN9 divided by the total number of NN intervals. F-J. HRV analyzed by frequency domain method. TP, total power; VLF, very low frequency; LF, low frequency; HF, high frequency; LF/HF, ratio of LF to HF. PSD, power spectral density. Data are shown as mean ± SD and analyzed by one-way ANOVA followed by Tukey’s multiple comparisons test. N = 8, 8, 6, 6, 8, and 8 respectively in Air, CIG, JUUL, IQOS, MJ, and pb-MJ group. * P<.05 compared to Air respectively; #P<.05 compared to CIG; ▲P<.05 compared to JUUL; ◆P<.05 compared to IQOS; ★P<.05 compared to MJ. Some p-values that are greater than .05 but may be of interest are noted here. In panel C, P=.17, Air compared to MJ; in panel F, P=.43, Air compared to JUUL; in panel H, P=.36, Air compared to IQOS; in panel I, P=.13, Air compared to MJ.