Measures of heart rate variability averaged over 24 h in patients with coronary heart disease (n=19) and healthy volunteers (n=31)
| Patients | Healthy volunteers | |||
| Filtered air | Diesel exhaust | Filtered air | Diesel exhaust | |
| Heart rate (bpm) | 62±2 | 60±2 | 71±2 | 71±2 |
| NN interval (ms) | 977±31 | 1008±28 | 848±22 | 843±20 |
| SDNN (ms) | 38±4 | 47±5 | 91±6 | 101±6 |
| RMSSD (ms) | 28±4 | 29±3 | 43±3 | 40±3 |
| PNN50 (%) | 10±4 | 9±3 | 20±2 | 18±3 |
| Triangular index | 7±1 | 8±1 | 21±1 | 20±1 |
| HF power (ms2) | 269±70 | 314±94 | 607±79 | 540±71 |
| LF power (ms2) | 622±182 | 693±245 | 1685±159 | 1533±144 |
| HFn (ms) | 33±5 | 33±5 | 23±2 | 23±1 |
| LFn (ms) | 65±5 | 65±6 | 75±2 | 75±1 |
| HF/LF ratio | 0.9±0.3 | 1.1±0.4 | 0.4±0 | 0.3±0 |
All variables are presented as mean±SEM.
Filtered air vs diesel exhaust, p>0.05 for all (paired t test).
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.