Table 4.
Correlation between various HRV parameters and disease duration, disease subtypes and presence of ACA.
| Parameter |
SSc duration |
DcSSc |
LcSSc |
ACA |
||||
|---|---|---|---|---|---|---|---|---|
| r | P | r | P | r | P | R | P | |
| Mean RR (ms) | −0.34 | 0.010 | −0.35 | 0.008 | −0.25 | 0.19 | −0.29 | 0.03 |
| SDNN (ms) | −0.08 | 0.560 | −0.20 | 0.14 | −0.06 | 0.76 | −0.15 | 0.26 |
| SDANN (ms) | −0.15 | 0.26 | −0.20 | 0.14 | −0.21 | 0.27 | −0.14 | 0.30 |
| SDNNi (ms) | 0.004 | 0.97 | −0.15 | 0.26 | 0.24 | 0.21 | −0.02 | 0.92 |
| rMSSD (ms) | 0.11 | 0.42 | 0.07 | 0.58 | 0.13 | 0.39 | 0.01 | 0.95 |
| pNN50 (%) | 0.16 | 0.25 | 0.13 | 0.35 | 0.11 | 0.55 | 0.09 | 0.60 |
| TP (ms2) | −0.10 | 0.47 | −0.26 | 0.05 | 0.09 | 0.62 | 0.05 | 0.77 |
| VLF (ms2) | −0.06 | 0.75 | −0.21 | 0.11 | 0.17 | 0.38 | 0.08 | 0.65 |
| LF (ms2) | −0.11 | 0.41 | −0.26 | 0.05 | 0.02 | 0.90 | −0.28 | 0.04 |
| HF (ms2) | −0.13 | 0.34 | −0.16 | 0.23 | 0.05 | 0.78 | −0.07 | 0.59 |
| LF/HF | 0.08 | 0.57 | −0.31 | 0.02 | −0.08 | 0.66 | 0.009 | 0.99 |
| PVCs ≥ 10/h | −0.29 | 0.03 | 0.004 | 0.97 | 0.14 | 0.30 | 0.07 | 0.58 |
| Total PVCs | 0.09 | 0.60 | −0.15 | 0.26 | −0.21 | 0.11 | −0.11 | 0.42 |
| SVT | −0.06 | 0.76 | 0.29 | 0.03 | −0.08 | 0.560 | 0.13 | 0.35 |
Abbreviations: SSc, systemic sclerosis; DcSSc, diffuse cutaneous SSc; LcSSc, limited cutaneous SSc; ACA, anti-centromere antibody; SDNN, standard deviation of all normal RR intervals in the entire 24-hr ECG recording; SDANN, standard deviation of the mean of normal RR intervals for each 5-min period of the 24 hr ECG recording; SDNNi, mean of the standard deviation of all normal RR intervals for all 5-min segments of a 24-hr ECG recording; rMSSD, root mean square successive difference between adjacent normal RR intervals over the entire 24-hr ECG recording; pNN50, percent of difference between adjacent normal RR intervals greater than 50 ms calculated over the entire 24-hr ECG recording; TP, variance of all NN intervals; VLF, power in the very low frequency range; LF, power in the low frequency range; HF, power in the high frequency range; LF/HF, ratio of LF (ms2) to HF (ms2); PVC, premature ventricular contractions; SVT, supravetricular tachycardia.