Table 2 •.

Univariate and Multivariate Cox Regression Analysis^a

Variable	Hazard Ratio	95% CI	P Value
Univariate
Ejection fraction	1.75	1.26–2.43	<.001
Peak $\stackrel{·}{\text{V}}$ o2 < 14 mL·	2.52	1.83–3.47	<.001
kg−1·min−1
${\stackrel{·}{\text{V}}}_{\text{E}}$/${\stackrel{·}{\text{V}}\text{co}}_2$ slope	3.19	2.28–4.46	<.001
HRR1	2.29	1.57–3.34	<.001
Multivariate
Ejection fraction	1.28	0.91–1.81	.15
Peak ${\stackrel{·}{\text{V}}\text{O}}_2$	1.62	1.15–2.29	.006
${\stackrel{·}{\text{V}}}_{\text{E}}$/${\stackrel{·}{\text{V}}\text{co}}_2$ slope	2.36	1.64–3.40	<.001
HHR1	1.70	1.14–2.51	.008

Abbreviations: ${\stackrel{·}{\text{V}}\text{O}}_2$, oxygen uptake; ${\stackrel{·}{\text{V}}}_{\text{E}}$/${\stackrel{·}{\text{V}}\text{co}}_2$ slope, minute ventilation/carbon dioxide production slope; HRR₁, heart rate recovery at the first minute.

^aAdjusted for ejection fraction, age, and etiology.