TABLE 2.

Energetics of hearts bearing cTnT mutations at baseline and at high workload in response to 4 mM Ca²⁺ or 300 nM dobutamine when not paced or paced at 420 bpm (n = 3-6)

	nTG			R-92L			R-92W
	Unpaced	Paced	Dobutamine	Unpaced	Paced	Dobutamine	Unpaced	Paced	Dobutamine
Baseline
Pi (mM)	2.7 ± 0.2	3.2 ± 0.2	2.8 ± 0.1	4.0 ± 0.2†	4.5 ± 0.2†	4.5 ± 0.6†	5.1 ± 0.3†‡	6.0 ± 0.2†‡	6.8 ± 0.3†¶
PCr (mM)	18.2 ± 0.3	18.2 ± 0.4	19.5 ± 0.1	14.1 ± 0.3†	14.3 ± 0.4†	15.4 ± 0.7†	12.9 ± 0.5†‡	12.5 ± 0.3†‡	13.6 ± 0.4†‡
ATP (mM)	10.0 ± 0.3	9.9 ± 0.3	9.9 ± 0.3	8.7 ± 0.2†	8.1 ± 0.2†	8.2 ± 0.5†	7.9 ± 0.2†‡	7.5 ± 0.3†	7.5 ± 0.5†
ADP (μM)	35 ± 2	35 ± 3	35 ± 1	55 ± 2*	50 ± 2*	44 ± 3†	63 ± 2†	62 ± 2†‡	55 ± 4†‡
High workload
Pi (mM)	6.0 ± 0.2‖	6.4 ± 0.3‖	8.4 ± 0.4‖	7.8 ± 0.2†‖	7.9 ± 0.1†‖	11.0 ± 0.5†‖	9.0 ± 0.2†‡‖	9.0 ± 0.2†‡‖	13.1 ± 0.6†‡‖
PCr (mM)	13.5 ± 0.2‖	13.3 ± 0.6‖	13.8 ± 0.1‖	10.5 ± 0.3†‖	10.6 ± 0.3†‖	10.2 ± 0.5†‖	8.5 ± 0.2†‡‖	8.6 ± 0.3†‡‖	7.9 ± 0.4†‡‖
ATP (mM)	9.8 ± 0.3	9.6 ± 0.4	9.6 ± 0.5	7.7 ± 0.1†‖	7.6 ± 0.3†	7.5 ± 0.4†	6.9 ± 0.2†‡§	6.6 ± 0.3*‡§	6.4 ± 0.2†‡§
ADP (μM)	71 ± 3‖	73 ± 3‖	78 ± 1‖	89 ± 6*‖	83 ± 7 *‖	87 ± 3*‖	109 ± 9*‡‖	100 ± 6†‡‖	117 ± 6†‡‖

Intracelluar pH in all hearts at baseline and high workload showed no differences, ranging from 7.08 to 7.13. ΔG_∼ATP is presented in Fig. 4. M, mol L⁻¹.

^*p < 0.05.

^†p < 0.01 vs. nTG.

^‡p < 0.05.

^¶p < 0.01 vs. R-92L.

^§p < 0.05.

^‖p < 0.01 vs. baseline.