Acute effect of exposure on heart rate variability in patients with coronary heart disease (n=19)
| Filtered air | Diesel exhaust | Two-way ANOVA p value | |||||
| Baseline | 2 h | 6 h | Baseline | 2 h | 6 h | ||
| Heart rate (bpm) | 62±2 | 60±2 | 59±2 | 62±2 | 60±2 | 59±2 | 0.595 |
| NN interval (ms) | 983±28 | 1010±29 | 1040±29 | 1010±25 | 1053±31 | 1052±30 | 0.080 |
| SDNN (ms) | 32±4 | 44±5 | 40±5 | 34±3 | 48±6 | 41±3 | 0.482 |
| RMSSD (ms) | 25±3 | 28±3 | 28±3 | 26±2 | 32±3 | 30±3 | 0.190 |
| PNN50 (%) | 6±2 | 9±2 | 9±2 | 7±2 | 13±3 | 12±3 | 0.072 |
| Triangular index | 7±1 | 8±1 | 8±1 | 7±1 | 8±1 | 8±1 | 0.897 |
| HF power (ms2) | 265±64 | 286±62 | 286±62 | 246±44 | 367±76 | 306±70 | 0.446 |
| LF power (ms2) | 508±152 | 794±200 | 673±207 | 407±107 | 748±293 | 541±76 | 0.494 |
| HFn (ms) | 37±4 | 32±4 | 34±3 | 41±5 | 40±5 | 34±4 | 0.215 |
| LFn (ms) | 60±4 | 65±4 | 63±3 | 56±5 | 57±5 | 63±4 | 0.211 |
| HF/LF ratio | 0.8±0.2 | 0.7±0.1 | 0.6±0.1 | 1.0±0.2 | 1.0±0.3 | 0.9±0.3 | 0.094 |
All variables are presented as mean±SEM.
Two-way ANOVA filtered air vs diesel exhaust at each time point.
HF, high frequency; HFn, normalised high frequency; LF, low frequency; LFn, normalised low frequency; PNN50, percentage of successive NN interval differences >50 ms; RMSSD, root mean square of successive NN interval differences; SDNN, SD of NN interval values.