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Figure 1 Absolute changes (mean ± SEM) from baseline in cardiac index after dobutamine (left figures) or enoximone (right figures) administration, before (open symbols) and after (closed symbols) long-term beta-blocker treatment with metoprolol (upper figures) or carvedilol (lower figures). Asterisks immediately above or below the standard error bars indicate significance of dose-specific differences from baseline. Asterisks between the dose-response curves indicate significance of dose-specific differences in the changes from baseline between before and after beta-blocker therapy. Significance values at the bottom of each graph indicate differences between the slopes of the dose response curves before and after metoprolol or carvedilol treatment. *p < 0.05; **p < 0.01; ***p < 0.001.