Table 2 Effects of inotropic modulation, heart rate and load modulation on contractile indices

Inotropy	Esmolol	Baseline	DBT	RMANOVA
Inotropy	Esmolol	Baseline	DBT	F value	p Value
SR_max (s⁻¹)	0.65 (0.13)*	1.05 (0.16)	1.88 (0.17)*†	63.755	<0.001
Mw (mW.s/ml)	1.36 (0.25)*	2.03 (0.10)	3.15 (0.36)*†	91.481	<0.001
ISA_max (s⁻²)	39 (8)*	90 (29)	224 (48)*†	53.799	<0.001

Pacing	HR 100	HR 120	HR 140	RMANOVA
Pacing	HR 100	HR 120	HR 140	F value	p Value
SR_max (s⁻¹)	1.15 (0.27)	1.24 (0.30)	1.29 (0.30)	1.955	0.192
Mw (mW.s/ml)	2.78 (0.52)	2.42 (0.27)	2.60 (0.55)	0.960	0.416
ISA_max (s⁻²)	54 (20)	70 (30)	88 (40)*	11.104	0.003

Loading	Baseline	Low preload	Baseline	High afterload
SR_max (s⁻¹)	1.19 (0.16)	1.14 (0.44)	1.05 (0.41)	0.73 (0.25)*
Mw (mW.s/ml)	2.17 (0.54)	2.08 (0.58)	2.19 (0.63)	2.47 (1.21)
ISA_max (s⁻²)	67 (28)	84 (21)	56 (22)	64 (45)

Values are means (SD).
DBT, dobutamine infusion at 3 μg/kg/min; HR, heart rate during atrial pacing in beats per minute; ISA_max, maximal isovolumic strain acceleration; Mw, slope of the preload recruitable stroke work relationship; RMANOVA, repeated measurements analysis of variance; SR_max, maximal strain rate.
*p<0.05 in comparison with baseline or HR 100.
†p<0.05 DBT in comparison with esmolol.