Table 2.
Heart Rate Variability and Environmental Measures by Examination, the Environmental Epidemiology of Arrhythmogenesis in the Women's Health Initiative, 1993–2004a
| Measure | Examination 1 (n = 4,097) |
Examination 2 (n = 3,429) |
Examination 3 (n = 2,459) |
||||||
| Mean (SE) | 10th Percentile | 90th Percentile | Mean (SE) | 10th Percentile | 90th Percentile | Mean (SE) | 10th Percentile | 90th Percentile | |
| RR, milliseconds | 932 (2.8) | 761 | 1,114 | 936 (3.0) | 763 | 1,118 | 942 (3.4) | 773 | 1,111 |
| SDNN, milliseconds | 20 (0.4) | 7 | 37 | 20 (0.4) | 6 | 36 | 19 (0.4) | 6 | 34 |
| RMSSD, milliseconds | 22 (0.5) | 7 | 40 | 21 (0.5) | 6 | 39 | 21 (0.6) | 7 | 38 |
| PM10, μg/m3b | 28 (0.2) | 16 | 42 | 27 (0.2) | 16 | 42 | 27 (0.3) | 16 | 41 |
| Temperature, °Cb | 14 (0.2) | 1 | 25 | 14 (0.2) | 1 | 24 | 14 (0.2) | 1 | 25 |
| Dew point, °Cb | 8 (0.2) | −5 | 19 | 8 (0.2) | −5 | 19 | 8 (0.2) | −5 | 19 |
| Barometric pressure, kPab | 102 (0.01) | 101 | 102 | 102 (0.01) | 101 | 102 | 102 (0.01) | 101 | 102 |
Abbreviations: PM10, particulate matter of <10 μm in diameter; RMSSD, root mean square of successive differences in normal-to-normal RR intervals; RR, median RR interval across all 12 leads; SDNN, standard deviation of normal-to-normal RR intervals; SE, standard error.
a
Summary statistics were weighted for sampling design and attrition.
b
Daily means were averaged over a 2-day period ending on the examination date (lag0−1).