Fig. 2.
Length-tension relationship, force-frequency relationship, and β-adrenergic stimulation in nonfailing vs. failing right ventricular myocardium. A: length-tension relationship is not different (at 0.5 Hz stimulation frequency) between nonfailing and failing myocardium (ANOVA, P > 0.05). Lopt, optimal length; L90, 90% of Lopt; L95, 95% of Lopt. B: force-frequency relationship is negative in failing myocardium. C: β-adrenergic response is shifted to the right in failing myocardium. D: EC50 is significantly greater in failing myocardium. *P < 0.05 as determined with 2-way ANOVA; $post hoc t-test indicating a significant difference of P < 0.05 between failing and nonfailing groups; #P < 0.05 as determined with unpaired t-test between nonfailing and failing groups. n = 8 nonfailing hearts, n = 8–9 failing hearts (1–3 trabeculae/heart).