Table 2.
Measures of heart rate variability at baseline in patients grouped by survival state
| Survivors (n=204) | Nonsurvivors (n=77) | P | |
|---|---|---|---|
| SDNN, ms | 95.8 (70.8–120.9) | 86.5 (55.9–106.1) | 0.007 |
| SDANN, ms | 87.1 (66.9–111.4) | 79.8 (51.6–97.9) | 0.008 |
| RMSSD, ms | 13.9 (10.2–18.0) | 13.2 (10.0–17.6) | 0.60 |
| pNN50, ms | 0.40 (0.04–1.77) | 0.23 (0.02–1.63) | 0.65 |
| HRVTI, ms | 24.3 (18.1–31.4) | 19.8 (15.0–27.8) | 0.001a |
| ULF, ln (ms2) | 8.78 (8.03–9.35) | 8.29 (7.64–9.00) | <0.001a |
| VLF, ln (ms2) | 6.19 (5.41–6.78) | 5.56 (4.61–6.40) | <0.001a |
| LF, ln (ms2) | 4.51 (3.71–5.35) | 4.02 (2.75–4.84) | 0.004 |
| HF, ln (ms2) | 3.80 (3.08–4.46) | 3.69 (2.92–4.38) | 0.38 |
| LF/HF | 1.92 (1.17–3.52) | 1.18 (0.82–2.26) | <0.001a |
| Scaling exponent α1 | 1.17 (0.98–1.34) | 1.01 (0.77–1.15) | <0.001a |
| Scaling exponent α2 | 1.20 (1.16–1.25) | 1.24 (1.18–1.29) | <0.001a |
| HRT category, 0/1/2, n (%)b | 20 (29.4%)/29 (42.7%)/19 (27.9%) | 5 (13.5%)/12 (32.4%)/20 (54.1%) | 0.02 |
| DC, ms | 4.33 (3.31–5.68) | 3.81 (2.61–4.70) | <0.001a |
Data are the median (interquartile range) unless otherwise indicated. 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.
Significant after correcting for multiple comparisons of 14 variables (P<0.003 for type 1 error level of 0.05).
Data were obtained only in patients with >5 ventricular ectopic beats (per day) suitable for HRT analysis.