Table 3.
Contribution of ENDO/EPI differences in the electrical, calcium handling and mechanical properties to the characteristics of action potential, Ca2+ transient, and contraction at isometric twitches
| Model | APD90, ms | CaT90, ms | T max, ms | TR75, ms |
|---|---|---|---|---|
| EPI | 204 | 71 | 115 | 131 |
| ENDO (E) | 256/1.25 | 69/0.97 | 122/1.06 | 149/1.14 |
| ENDO (E + Ca) | 259/1.27 | 80/1.12 | 140/1.22 | 176/1.34 |
| ENDO | 262/1.28 | 97/1.37 | 154/1.34 | 175/1.34 |
| ENDO (−MEF) | 256/1.25 | 82/1.15 | 158/1.37 | 178/1.36 |
The ENDO/EPI ratio for the characteristics produced by the models is shown after the slash
APD 90 action potential duration at 90% repolarization, CaT 90 calcium transient duration at 90% decay, T max time to peak contraction, TR 75 time to 75% relaxation (measured as the time interval from T max to the time of 75% relaxation). ENDO (E) model differs from the EPI model in the electrical properties only; ENDO (E + Ca) model accounts for the heterogeneity in the electrical and calcium handling properties between the cells; ENDO is a complete ENDO model accounting for the heterogeneity in the electrical, calcium handling and mechanical properties; ENDO (−MEF) model is a complete ENDO model excluding mechano-calcium-electric feedback (MEF)