Table 2.
Derived cross-bridge parameters for PTU and PO hearts
| PTU (n = 5) | PO (n = 6) | ||
|---|---|---|---|
| Thermomechanical measurement | |||
| Cross-bridge force–time integral, entire twitch | FTIXBr,Tw (pN s) | 0.30 ± 0.03 | 0.49 ± 0.06 * |
| Cross-bridge force–time integral, peak of twitch | FTIXBr,0.9Po (pN s) | 0.45 ± 0.05 | 0.80 ± 0.10 * |
| Two-state model derivation | |||
| Unitary force | Funi (pN) | 2.7 ± 0.3 | 5.8 ± 0.9 * |
| Average force | Favg (pN) | 0.67 ± 0.05 | 0.61 ± 0.05 |
| Attachment time | Tatt (ms) | 170 ± 20 | 150 ± 20 |
| Cycle time | Tcycle (ms) | 690 ± 70 | 1190 ± 150 * |
| Cycling rate | CR (s−1) | 1.50 ± 0.14 | 0.89 ± 0.10 * |
| Duty cycle | DC | 0.24 ± 0.02 | 0.14 ± 0.03 * |
| Attachment rate | fapp (s−1) | 2.0 ± 0.2 | 1.0 ± 0.1 * |
| Detachment rate | gapp (s−1) | 6.3 ± 0.7 | 7.2 ± 1.0 |
Values are means ±s.e.m. Statistically significant differences (P < 0.05, Student's unpaired t test) are marked with an asterisk.