Table 4.

Unadjusted and adjusted HRs of HRV measures for mortality risk

PredictorUnitUnadjustedAdjusteda
HR (95% CI)bPHR (95% CI)bP
SDNN−25 ms1.30 (1.09–1.55)0.0041.08 (0.90–1.30)0.42
SDANN−25 ms1.32 (1.09–1.59)0.0041.09 (0.89–1.33)0.40
RMSSD−1.5 ms1.00 (0.96–1.03)0.891.00 (0.97–1.04)0.78
pNN50−1.5 ms0.99 (0.92–1.05)0.641.02 (0.95–1.09)0.63
HRVTI−101.24 (1.10–1.40)<0.001c1.14 (0.85–1.52)0.39
ULF−0.5 ln (ms2)1.24 (1.10–1.40)<0.001c1.09 (0.95–1.25)0.21
VLF−0.5 ln (ms2)1.18 (1.08–1.29)<0.001c1.07 (0.96–1.18)0.22
LF−5 ln (ms2)3.55 (1.63–7.70)0.001c1.83 (0.77–4.31)0.16
HF−5 ln (ms2)1.85 (0.62–5.46)0.261.17 (0.41–3.29)0.76
LF/HF−55.17 (2.12–12.62)<0.001c2.85 (1.10–7.35)0.03
Scaling exponent α1−0.251.75 (1.41–2.16)<0.001c1.46 (1.16–1.85)0.001c
Scaling exponent α20.253.73 (1.86–7.49)<0.001c1.25 (0.61–2.53)0.54
HRT categoryd0, 1, 21.95 (1.22–3.11)0.0051.34 (0.81–2.22)0.26
DC−1 ms1.36 (1.15–1.60)<0.001c1.13 (0.96–1.34)0.14
  • HR, hazard ratio; HRV, heart rate variability; SDNN, SD of normal-to-normal intervals during 24 hours; SDANN, SD of the averages of NN intervals in all 5-minute segments during 24 hours; RMSSD, square root of the mean square of differences between adjacent NN intervals; pNN50, percentage of the number of pairs of adjacent NN R-R intervals differing >50 ms in the total NN intervals; HRVTI, heart rate variability triangular index; ULF, ultra-low frequency (≤0.003 Hz) power; VLF, very-low frequency (0.003–0.04 Hz) power; LF, low frequency (0.04–0.15 Hz) power; HF, high frequency (0.15–0.40 Hz) power; HRT, heart rate turbulence; DC, deceleration capacity.

  • a Adjusted for age, left ventricular ejection fraction, serum albumin, C-reactive protein, and calcium × phosphate.

  • b HR for 1 unit change in continuous variables or for the presence of features.

  • c Significant after correcting for multiple analyses of 14 variables (P<0.003 for type 1 error level of 0.05).

  • d n=68 for survivors and n=37 for nonsurvivors.