Table 1.
Patient characteristics at baseline by intervention group
| HRV-biofeedback | Usual care | p-valuea | |
|---|---|---|---|
| n = 23 | n = 23 | ||
| Age (years) | 57.4 ± 8.8 | 63.6 ± 9.9 | 0.029 |
| Male gender | 21 (91.3) | 18 (78.3) | 0.414 |
| Years since last MI | 5 (2;8) | 3 (2;5) | 0.066 |
| Long-time measures (24 h) | |||
| Systolic blood pressure (mm Hg) | 123.9 ± 10.9 | 130.1 ± 12.2 | 0.075 |
| SDNN (ms) | 129.0 ± 47.7 | 130.0 ± 41.2 | 0.944 |
| SDNN (ms), log | 4.8 ± 0.4 | 4.8 ± 0.3 | 0.761 |
| Short-time measures (5 min) | |||
| Breathing rate (1/min) | 12.6 ± 5.3 | 13.6 ± 4.2 | 0.478 |
| Heart rate (bpm) | 67.2 ± 12.4 | 64.6 ± 7.1 | 0.396 |
| Heart rate (bpm), log | 4.2 ± 0.2 | 4.2 ± 0.1 | 0.515 |
| SDNN (ms) | 31.7 (24;41) | 24.6 (21;33) | 0.118 |
| SDNN (ms), log | 3.4 ± 0.5 | 3.3 ± 0.3 | 0.177 |
| HF | 56.5 (21;120) | 91.0 (49;136) | 0.170 |
| HF, log | 4.0 ± 1.2 | 4.6 ± 1.5 | 0.162 |
| LF | 289.6 (94;1103) | 122.7 (52;224) | 0.048 |
| LF, log | 5.6 ± 1.5 | 4.8 ± 1.4 | 0.091 |
| Psychological measures | |||
| WHO-5 Well-being | 17 (9;19) | 18 (14;20) | 0.223 |
| WHO-5, squared | 241.0 ± 162.5 | 294 ± 138.2 | 0.244 |
| ASKU Self-Efficacy | 4.1 ± 0.5 | 4.2 ± 0.4 | 0.225 |
| SSCS-TICS Chronic Stress | 17.7 ± 10.4 | 16.7 ± 9.2 | 0.734 |
Data are absolute numbers and percentages, mean values ± standard deviation, medians, and quartiles
MI myocardial infarction
ap-value based on Student’s t-test (with or without equal variances), Wilcoxon rank sum test, or Fisher’s exact test for small sample sizes