Effect of cGMP on nonfailing (A) and failing (B) myocardium. C, Comparison of effect of cGMP in failing and nonfailing myocardium. Solid line and •, control in nonfailing myocardium; dotted line and ○, 10 μmol/L 8-bromo-cGMP in nonfailing myocardium; solid line and ▾, control in failing myocardium; and dotted line and ▿, 10 μmol/L 8-bromo-cGMP in failing myocardium.