Table 2.
Lower-body negative pressure responses
| Two-Way ANOVA |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Lower-Body Negative Pressure | Baseline | −10 | −20 | −30 | Time | Trial | Time × Trial | |||
| Stroke volume, ml | ||||||||||
| Control | 106 ± 13 | 102 ± 12 | 100 ± 12 | 97 ± 12 | 97 ± 13 | 93 ± 14 | 90 ± 14 | 0.000 | 0.687 | 0.086 |
| Prazosin | 106 ± 12 | 103 ± 14 | 99 ± 16 | 96 ± 15 | 93 ± 16 | 91 ± 16 | 85 ± 18* | |||
| Cardiac output, l/min | ||||||||||
| Control | 6.4 ± 1.2 | 6.1 ± 1.1 | 6.1 ± 1.1 | 5.9 ± 1.1 | 6.0 ± 1.0 | 5.8 ± 1.0 | 5.9 ± 1.0 | 0.642 | 0.002 | 0.162 |
| Prazosin | 7.1 ± 1.4 | 7.1 ± 1.2 | 7.2 ± 1.4 | 7.2 ± 1.0 | 7.4 ± 0.9 | 7.5 ± 0.8 | 7.3 ± 0.9 | |||
| Heart rate, beats/min | ||||||||||
| Control | 61 ± 12 | 60 ± 12 | 61 ± 13 | 62 ± 13 | 63 ± 13 | 64 ± 14 | 67 ± 14 | 0.000 | 0.002 | 0.009 |
| Prazosin | 68 ± 16 | 70 ± 16 | 75 ± 20 | 77 ± 17* | 82 ± 17* | 84 ± 17* | 89 ± 17* | |||
| Diastolic BP, mmHg | ||||||||||
| Control | 77 ± 9 | 77 ± 9 | 77 ± 9 | 78 ± 9 | 78 ± 9 | 79 ± 9 | 79 ± 10 | 0.177 | 0.160 | 0.060 |
| Prazosin | 73 ± 8 | 74 ± 8 | 72 ± 9 | 74 ± 8 | 73 ± 8 | 74 ± 9 | 73 ± 9 | |||
| Systolic BP, mmHg | ||||||||||
| Control | 132 ± 7 | 131 ± 6 | 129 ± 7 | 130 ± 7 | 131 ± 6 | 130 ± 7 | 131 ± 7 | 0.152 | 0.388 | 0.005 |
| Prazosin | 131 ± 9 | 131 ± 9 | 128 ± 9 | 129 ± 9 | 127 ± 10 | 127 ± 10 | 124 ± 11 | |||
| Rate pressure product | ||||||||||
| Control | 8,048 ± 1,746 | 7,923 ± 1,745 | 7,929 ± 1,831 | 8,024 ± 1,766 | 8,192 ± 1,741 | 8,348 ± 1,895 | 8,708 ± 1,916 | <0.001 | 0.027 | 0.025 |
| Prazosin | 8,954 ± 2,618 | 9,253 ± 2,537 | 9,646 ± 2,963 | 9,969 ± 2,491* | 10,479 ± 2,585* | 10,751 ± 2,568* | 10,960 ± 2,319* | |||
| LAD VTI | ||||||||||
| Control | 12.1 ± 2.7 | 11.1 ± 3.6 | 9.9 ± 3.4 | 8.7 ± 1.3 | 0.019 | 0.09 | 0.547 | |||
| Prazosin | 9.5 ± 0.9 | 9.8 ± 1.9 | 8.1 ± 2.2 | 7.8 ± 1.8 | ||||||
| LAD velocity max | ||||||||||
| Control | 0.277 ± 0.05 | 0.26 ± 0.06 | 0.243 ± 0.05 | 0.226 ± 0.03 | 0.029 | 0.52 | 0.621 | |||
| Prazosin | 0.25 ± 0.06 | 0.249 ± 0.03 | 0.226 ± 0.04 | 0.225 ± 0.04 | ||||||
| LAD velocity mean | ||||||||||
| Control | 0.21 ± 0.03 | 0.19 ± 0.03 | 0.203 ± 0.04 | 0.187 ± 0.03 | 0.496 | 0.973 | 0.177 | |||
| Prazosin | 0.197 ± 0.03 | 0.207 ± 0.02 | 0.188 ± 0.03 | 0.20 ± 0.03 | ||||||
Hemodynamic and coronary responses during lower-body negative pressure test (averaged per 2-min stages). P values refer to two-way repeated-measures ANOVAs, for within-participant comparison (time), between-trial comparison, and the interaction time × trial. BP, blood pressure; LAD, left anterior descending (coronary artery).
*
Significant difference compared with baseline values, P < 0.05. Italicized values indicate significant difference (P < 0.05).