Table 1.
Right ventricular cardiomyocyte characterization
| Parameter | Control | HFpEF | ||
|---|---|---|---|---|
| Stimulation frequency | Mean ± SEM | P‐values | ||
| Cell shortening (CS) | ||||
| CS amplitude (%) | 1 Hz | 5.72 ± 0.51 | 4.48 ± 1.03 | 0.3646 |
| 2 Hz | 7.16 ± 0.63 | 5.72 ± 0.86 | 0.2163 | |
| Sarcomere length (μm) | 1 Hz | 1.79 ± 0.01 | 1.84 ± 0.04 | 0.1724 |
| 2 Hz | 1.77 ± 0.01 | 1.79 ± 0.01 | 0.6040 | |
| CS TTP (ms) | 1 Hz | 145.40 ± 11.35 | 162.80 ± 5.35 | 0.1656 |
| 2 Hz | 126.00 ± 9.27 | 142.5 ± 6.29 | 0.2122 | |
| CS RT50 (ms) | 1 Hz | 241.20 ± 25.25 | 285.20 ± 25.73 | 0.1513 |
| 2 Hz | 192.00 ± 15.38 | 200.30 ± 9.30 | 0.7929 | |
| CS RT90 (ms) | 1 Hz | 401.20 ± 25.47 | 518.80 ± 68.16 | 0.0526 |
| 2 Hz | 262.80 ± 23.42 | 290.00 ± 3.67 | 0.6528 | |
| CS Tau (s) | 1 Hz | 0.11 ± 0.02 | 0.19 ± 0.05 | 0.0603 |
| 2 Hz | 0.08 ± 0.02 | 0.09 ± 0.01 | 0.8703 | |
| Calcium transients (CaT)—epifluorescence | ||||
| CaT amplitude (F 340/F 380 ratio) | 1 Hz | 0.41 ± 0.02 | 0.22 ± 0.02 | <0.005 |
| 2 Hz | 0.42 ± 0.02 | 0.23 ± 0.03 | <0.005 | |
| 4 Hz | 0.42 ± 0.02 | 0.21 ± 0.03 | <0.005 | |
| Systolic cytosolic [Ca2+] | 1 Hz | 1.16 ± 0.02 | 0.97 ± 0.05 | <0.05 |
| 2 Hz | 1.23 ± 0.03 | 0.99 ± 0.05 | <0.005 | |
| 4 Hz | 1.29 ± 0.05 | 1.00 ± 0.06 | <0.01 | |
| Diastolic cytosolic [Ca2+] | 1 Hz | 0.75 ± 0.01 | 0.73 ± 0.03 | 0.6003 |
| 2 Hz | 0.81 ± 0.02 | 0.77 ± 0.03 | 0.3112 | |
| 4 Hz | 0.89 ± 0.04 | 0.83 ± 0.03 | 0.2991 | |
| CaT TTP (ms) | 1 Hz | 40.20 ± 2.04 | 61.00 ± 3.54 | <0.005 |
| 2 Hz | 40.00 ± 4.47 | 60.00 ± 3.16 | <0.01 | |
| 4 Hz | 42.00 ± 2.00 | 52.00 ± 2.00 | <0.01 | |
| CaT RT50 (ms) | 1 Hz | 204.20 ± 9.48 | 233.60 ± 13.67 | <0.05 |
| 2 Hz | 158.60 ± 9.50 | 177.40 ± 4.47 | 0.1174 | |
| 4 Hz | 119.20 ± 2.78 | 122.80 ± 2.69 | 0.7585 | |
| CaT RT90 (ms) | 1 Hz | 555.60 ± 29.20 | 603.00 ± 56.16 | 0.2263 |
| 2 Hz | 338.20 ± 6.56 | 366.60 ± 13.74 | 0.4735 | |
| 4 Hz | 191.20 ± 10.22 | 211.00 ± 5.34 | 0.6087 | |
| CaT Tau (s) | 1 Hz | 0.25 ± 0.02 | 0.28 ± 0.05 | 0.5464 |
| 2 Hz | 0.18 ± 0.02 | 0.18 ± 0.02 | 0.9156 | |
| 4 Hz | 0.14 ± 0.02 | 0.23 ± 0.08 | 0.0945 | |
| Cardiomyocyte myofilament sensitivity | ||||
| Peak Ca2+ to systolic sarcomere length ratio | 1 Hz | 0.69 ± 0.01 | 0.55 ± 0.03 | 0.0087 |
| Slope (a.u.) | 1 Hz | 23.83 ± 2.78 | 38.60 ± 7.36 | 0.0396 |
Cell shortening (CS); CS amplitude, %; diastolic sarcomere length, μm; CS time to peak (TTP), ms; CS time to 50% baseline (RT50), ms; CS time to 90% baseline (RT90), ms; CS relaxation time constant (Tau), s; calcium transients amplitude (CaT), F 340/F 380 ratio; systolic cytosolic [Ca2+] concentration; diastolic cytosolic [Ca2+] concentration; CaT time to peak (TTP), ms; CaT time to 50% baseline (RT50), ms; CaT time to 90% baseline (RT90), ms; CaT time constant (Tau), s; peak Ca2+ to systolic sarcomere length ratio; slope of cardiomyocyte myofilament sensitivity, a.u.; cell shortening measurements were performed at 1 and 2 Hz stimulation. Epifluorescence measured calcium transients were performed at 1, 2, and 4 Hz stimulation. Control, Wistar Kyoto rats. Four to five animals per group with an average of 16 cells per animal. Error bars represent standard error of the mean (SEM).