The Cardiac Sympathetic Nerve Activity in the Elderly Is Attenuated in the Right Lateral Decubitus Position

Figures

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  Figure 1.. Comparison of indexes of HRV (a-c), HR (d) and respiratory rate (e) in the supine, left lateral decubitus, and right lateral decubitus positions. Note. The asterisks indicate statistical significance between two positions. As for nonparametric analysis of LF/HF (c), a p value of .0167 or lower was considered statistically significant, using Bonferroni correction as a post hoc test after the Friedman test. HRV = heart rate variability; HR = heart rate; LF = low frequency; HF = high frequency; LF/HF = the ratio of LF to HF; bpm = beats per minute.

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  Figure 2.. Time-course changes in HR for 10 min among the three positions. Note. The upper, middle, and lower lines indicate the HR in the supine position, right lateral decubitus position, and left lateral decubitus position, respectively. Mean ± standard deviation. HR = heart rate; Supine = supine position; LLD = left lateral decubitus position; RLD = right lateral decubitus position; bpm = beats per minute; min = minute.

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  Figure 3.. Correlation between LF/HF in the supine position and changes in LF/HF. Note. Changes in LF/HF were determined as differences in the actual measurements between the supine and right lateral decubitus positions. Black circles, black triangles, and crosses represent the individual data of the 45 participants in the healthy, HT, and CAD groups, respectively. LF/HF = the ratio of the low frequency component to the high frequency component; HT = hypertension; CAD = coronary artery disease.