Table 2.
Clinical characteristics and results of HRV analysis of studied healthy children in three age groups with results of the Kruskal-Wallis test.
| 1st age group 3-6 years old N = 7 | 2nd age group 7–12 years old N = 28 | 3rd age group 13–18 years old N = 65 | K-W test p-value | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean | SD | Median | 25th p. | 75th p. | Mean | SD | Median | 25th p. | 75th p. | Mean | SD | Median | 25 | 75 P | ||
| Age [years] | 4.4 | 1.3 | 4.0 | 3.3 | 5.8 | 9.6 | 1.7 | 10.0 | 8.0 | 11.0 | 15.5 | 1.6 | 15.0 | 14.8 | 17.0 | |
| PQ [ms] | 118.9 | 8.7 | 120.0 | 110.5 | 127.5 | 127.9 | 18.0 | 128.0 | 114.0 | 140.0 | 131.2 | 15.7 | 130.0 | 120.0 | 140.0 | 0.1120 |
| QRS [ms] | 77.0 | 13.0 | 80.0 | 65.5 | 87.5 | 83.3 | 8.1 | 81.0 | 79.0 | 90.0 | 87.3 | 8.1 | 86.0 | 80.0 | 90.0 | 0.0270 |
| QTc [ms] | 388.7 | 22.2 | 388.0 | 373.8 | 395.0 | 391.8 | 16.4 | 393.0 | 381.0 | 401.5 | 393.9 | 21.2 | 395.0 | 379.5 | 410.5 | 0.6176 |
| Supraventricular beats in 24-h ECG [%] | 0 | 0 | 0 | 0 | 0 | 0.8 | 2.8 | 0 | 0 | 0 | 1.1 | 5.4 | 0 | 0 | 0 | 0.5739 |
| Ventricular beats in 24-h ECG [%] | 0.4 | 1.1 | 0 | 0 | 0 | 0.2 | 1.0 | 0 | 0 | 0 | 1.5 | 4.4 | 0 | 0 | 0 | 0.5274 |
| Duration of ECG recording [min] | 1312.3 | 44.1 | 1327.5 | 1277.2 | 1345.6 | 1311 | 101.6 | 1306.1 | 1235.4 | 1419.2 | 1293.8 | 108.6 | 1293.8 | 1223.2 | 1380.3 | 0.8001 |
| Mean RR [ms] | 643.2 | 40.1 | 656.7 | 621.0 | 668.8 | 701.1 | 73.2 | 705.8 | 637.1 | 756.8 | 767.9 | 70.8 | 770.1 | 714.1 | 812.8 | 0.0000 |
| SDNN [ms] | 125.5 | 34.3 | 126.3 | 93.7 | 147.8 | 148.0 | 42.4 | 139.3 | 118.0 | 177.9 | 166.6 | 39.3 | 165.6 | 139.6 | 192.6 | 0.0111 |
| ULF [ms2] | 11638.2 | 7240.5 | 7617.0 | 6955.2 | 16066.3 | 16741.7 | 10074.6 | 13420.9 | 9735.0 | 21376.7 | 23528.6 | 11732.1 | 23091.7 | 14798.3 | 31390.6 | 0.0006 |
| VLF [ms2] | 1982.0 | 1172.1 | 1891.0 | 1102.1 | 2739.2 | 3169.6 | 1730.7 | 2475.7 | 1870.1 | 4152.9 | 4129.6 | 1984.3 | 3919.1 | 2787.9 | 5191.7 | 0.0025 |
| LF [ms2] | 1171.9 | 682.4 | 1213.8 | 717.6 | 1358.3 | 1809.3 | 1022.8 | 1558.6 | 1048.6 | 2444.5 | 2186.7 | 1174.9 | 1977.6 | 1338.6 | 2839.3 | 0.0304 |
| HF [ms2] | 1646.0 | 1462.8 | 1537.1 | 548.0 | 2252.4 | 2258.1 | 2563.8 | 1372.1 | 734.8 | 2726.5 | 1772.9 | 1606.2 | 1476.4 | 676.7 | 2058.0 | 0.8695 |
| LF/HF [] | 1.0 | 0.6 | 0.8 | 0.6 | 1.1 | 1.2 | 0.6 | 1.1 | 0.9 | 1.5 | 1.6 | 0.7 | 1.6 | 1.2 | 2.2 | 0.0031 |
| SD1 [ms] | 51.7 | 27.4 | 59.5 | 25.4 | 67.2 | 51.0 | 29.1 | 45.1 | 28.6 | 66.2 | 47.8 | 22.4 | 44.5 | 32.3 | 55.9 | 0.9314 |
| SD2 [ms] | 168.7 | 44.6 | 168.4 | 129.3 | 195.5 | 201.3 | 55.5 | 191.0 | 162.3 | 238.9 | 229.2 | 53.8 | 230.4 | 190.7 | 267.5 | 0.0039 |
| CL [%] | 91.4 | 6.7 | 92.8 | 89.4 | 96.3 | 94.0 | 4.6 | 95.5 | 92.4 | 97.2 | 95.5 | 3.7 | 96.6 | 94.6 | 97.7 | 0.0228 |