Table 2.
The effect of allopurinol and placebo on the mean plasma uric acid, indices of heart rate variability, mean heart rate and arrhythmias in the study groups and on heart rate variability in sub-groups of patients with significantly low baseline HRV (i), high plasma uric acid baseline (ii) or both (iii).
| Parameters | Baseline (mean ± s.d.) | Placebo (mean ± s.d.) | Allopurinol (mean ± s.d.) | P-value placebo vs. allopurinol | 95% CI placebo vs. allopurinol |
|---|---|---|---|---|---|
| Groups | |||||
| SDNN (ms) | 139 ± 56 | 137 ± 49 | 131 ± 52 | 0.18 | (− 3.4, 16.5) |
| SDANN (ms) | 118 ± 44 | 110 ± 37 | 113 ± 38 | 0.68 | (− 17, 11) |
| SDNNi | 68 ± 56 | 62 ± 42 | 66 ± 51 | 0.76 | (− 12, 16) |
| RMSSD (ms) | 45 ± 36 | 46 ± 33 | 45 ± 33 | 0.68 | (− 5.6, 3.7) |
| Triangular index | 35 ± 16 | 34 ± 13 | 31 ± 14 | 0.5 | (− 5.2, 0.8) |
| Log ventricular ectopies | 5.9 ± 1.7 | 5.7 ± 1.9 | 5.8 ± 1.8 | 0.7 | (− 0.5, 0.3) |
| Mean heart rate (beats min−1) | 68 ± 12 | 69 ± 10 | 70 ± 13 | 0.5 | (− 2, 3.8) |
| Plasma uric acid (mmol l−1) | 0.52 ± 0.08 | 0.52 ± 0.08 | 0.34 ± 0.05 | <0.0001 | (0.11, 0.22) |
| Subgroups | |||||
| (i) | |||||
| SDNNi (ms) | 32 ± 12 | 34 ± 10 | 34 ± 8 | 0.4 | (− 7.6, 3.7) |
| RMSSD (ms) | 26 ± 15 | 27 ± 13 | 30 ± 14 | 0.2 | (− 12, 3.4) |
| Triangular index | 20 ± 8 | 20 ± 9 | 20 ± 8 | 1 | (− 5.1, 4.8) |
| (ii) | |||||
| SDNNi (ms) | 67 ± 55 | 65 ± 53 | 66 ± 51 | 0.87 | (− 5.01, 5.7) |
| RMSSD (ms) | 47 ± 38 | 49 ± 37 | 50 ± 36 | 0.27 | (− 9.3, 2.8) |
| Triangular index | 35 ± 17 | 34 ± 16 | 32 ± 15 | 0.08 | (− 0.4, 6.4) |
| (iii) | |||||
| SDNNi (ms) | 32 ± 12 | 33 ± 10 | 34 ± 8 | 0.4 | (− 7.6, 3.7) |
| RMSSD (ms) | 22 ± 10 | 25 ± 9 | 27 ± 12 | 0.2 | (− 15, 12) |
| Triangular index | 19 ± 9 | 19 ± 88 | 20 ± 9 | 0.8 | (− 6.2, 5.5) |
HRV, heart rate variability; rMSSD, root-mean-square of the successive normal sinus RR interval difference; SDANN, standard deviation of the averaged normal sinus RR intervals for all 5 min segments; SDNN, standard deviation of all normal sinus RR intervals over 24 h; SDNNi, mean of the standard deviations of all normal sinus RR intervals for all 5 min segments; TI, triangular index; CI, confidence intervals.