Table 3.

Mixed linear analysis

Condition	Slope	P-value
Baseline	1.19 (1.06–1.31)
Afterload increased	1.18 (1.05–1.30)	0.092
Preload reduced	1.28 (1.16–1.41)	<0.001
Dobutamine	1.14 (1.01–1.26)	<0.001
Metoprolol	1.07 (0.94–1.20)	<0.001
Nitroprusside	1.10 (0.97–1.22)	<0.001

Baseline was used as the reference condition. The slope of the regression for each condition was significantly different from the slope of the reference condition, with the exception of the increased afterload condition. The lowest slope was associated with the metoprolol infusion and nitroprusside infusion conditions.