Cardiac autonomic dysfunction in patients with gastroesophageal reflux disease

Table 6 Short term heart rate variability analysis (mean ± SD)

Parameter	Reflux	Controls	P value1
Average dRR (ms)	15.67 ± 10.35	27.80 ± 17.49	0.003
SD dRR (ms)	12.48 ± 7.63	22.42 ± 13.87	0.001
MD dRR (ms)	9.76 ± 6.36	17.10 ± 10.25	0.002
pNN50%	3.62 ± 6.26	9.82 ± 10.29	0.009
RMSSD (ms)	19.81 ± 12.81	35.87 ± 21.78	0.001
VLF (ms2)	67.76 ± 65.56	129.33 ± 129.19	0.036
LF (ms2)	56.29 ± 65.64	135.07 ± 142.90	0.015
HF (ms2)	35.62 ± 51.27	102.52 ± 115.53	0.011
LF/HF	3.07 ± 2.34	2.27 ± 2.82	0.225

¹t-test. SD dRR: Standard deviation of normal RR intervals (SD); MD dRR: Absolute mean of standard deviation; pNN50%: Percentage of adjacent RR intervals differing > 50 ms; RMSSD: Mean square root of the mean of the sum of the squares of differences between adjacent RR intervals; VLF: Very low-frequency power; LF: Low-frequency power; HF: High-frequency power.