Impaired parasympathetic function in long-COVID postural orthostatic tachycardia syndrome – a case-control study

Table 3 Supine spectral analysis of BP and HR variability in Long-COVID POTS and Healthy controls

Parameters	Long-COVID POTS	Healthy	P value
	N = 13	N = 16
RMSSD	32.1 ± 4.6	48.9 ± 6.8	0.04
SD1	22.8 ± 3.3	34.2 ± 4.9	0.08
SD2	59.3 ± 5.4	67.7 ± 5.7	0.30
Total Power RRI	1671 ± 350	2467 ± 544	0.29
LF_RRI (ms²)	756 ± 174	982 ± 274	0.89
LF_RRI n.u.	66 ± 4	54 ± 4	0.06
HF_RRI (ms²)	349 ± 105	851 ± 253	0.03
HF_RRI n.u.	32 ± 4	46 ± 4	0.02
LF/HF	3.0 ± 0.7	1.2 ± 0.3	0.01
LF_SBP (mmHg²)	3.3 ± 1.0	4.6 ± 0.8	0.11
HF_SBP (mmHg²)	1.6 ± 0.4	1.8 ± 0.7	0.78

Values are means ± SEM. RMSSD indicates root mean square of standard deviations; SD1 and SD2, Pointcare plots standard deviation 1 and 2; RRI R-R interval, SBP Systolic blood pressure, LF Low frequency bands, HF High frequency bands. P values obtained using Student’s t-test or Mann-Whitney test

ISSN: 2332-8886