Evaluation of left ventricular mechanical work and energetics of normal hearts in SERCA2a transgenic rats

Table 2 Variables of left ventricular mechanical work at a pacing of 300 bpm

Variables	WT (n = 8)	TGI (n = 4)	TGII (n = 5)
ESPVR^a
A (mmHg)	196.2 ± 48.4	208.1 ± 40.5	199.5 ± 51.0
B (ml⁻¹)	17.3 ± 9.6	23.1 ± 9.5	12.7 ± 7.3
V ₀ (×10⁻² ml g⁻¹)	8.06 ± 1.09	9.97 ± 0.70	9.46 ± 0.94
EDPVR^a
A′ (mmHg)	0.096 ± 0.11	0.045 ± 0.053	0.069 ± 0.094
B′ (ml⁻¹)	40.2 ± 17.3	30.7 ± 4.3	34.4 ± 9.6
ESP_mLVV (mmHg)	129.3 ± 30.8	175.3 ± 36.3*^{, #}	116.5 ± 21.9
PVA_mLVV (mmHg ml beat⁻¹ g⁻¹)	6.55 ± 2.10	12.36 ± 4.26*^{, #}	7.02 ± 2.77
mLVV (ml g⁻¹)	0.166 ± 0.022	0.200 ± 0.037	0.189 ± 0.018

*P < 0.05 vs. WT; ^# P < 0.05 versus TGII
Values are presented as the mean ± SD
mLVV midrange left ventricular volume, ESP _mLVV end-systolic pressure at mLVV, PVA _mLVV systolic pressure–volume area at mLVV, V ₀ volume intercept of ESPVR normalized by LV mass to 1 g
^a A, B, Parameters of best-fit end-systolic pressure–volume relation (ESPVR) obtained by ESP = A{1 − exp[−B(V − V ₀)]}; A′, B′ parameters of best-fit end-diastolic pressure–volume relation (EDPVR) obtained by ESP = A′{1 − [exp(−B′(V − V _u))]⁻¹}. Each best-fit curve was obtained by ESP-V data during left ventricular (LV) volume-loading run

ISSN: 1880-6562