Table 1.

 Physiologic response to study drug administration

	Pre-operative BB	Study drug		Difference between placebo and metoprolol	*p Value
		Metoprolol	Placebo
Change between baseline and 8 hours in ICU
Heart rate	Yes	−2.39 (9.80)	−0.41 (9.05)	1.98 (9.44)	0.0022
	No	−5.74 (11.42)	1.03 (9.87)	6.77 (10.61)
Cardiac index	Yes	−0.13 (0.67)	−0.082 (0.64)	0.051 (0.66)	0.0018
	No	−0.34 (0.80)	−0.016 (0.72)	0.32 (0.76)
PAWP	Yes	0.51 (3.32)	−0.45 (3.23)	−0.96 (3.28)	0.17
	No	0.61 (3.68)	0.41 (3.15)	−0.19 (3.41)
Change between baseline and day 4
Heart rate	Yes	−4.27 (16.43)	4.98 (17.20)	9.25 (16.82)	0.50
	No	−5.93 (16.45)	1.11 (14.47)	7.04 (15.46)

Figures are presented as mean and standard deviation of mean.

*Unadjusted p values of interaction (p value tests for an interaction between pre-operative BB use and study drug).

BB, β blocker; ICU, intensive care unit; PAWP, pulmonary artery wedge pressure.