Basal and Isoprenaline-Stimulated cAMP Content in Failing Versus Nonfailing Human Cardiac Preparations

We measured force of contraction and cAMP content in human isolated electrically driven right ventricular trabeculae carneae with and without the addition of isoprenaline (0.2 μM). Basal cAMP content was ∼200% higher in preparations from nonfailing hearts than from hearts with end-stage myocardial failure. Isoprenaline was less effective in increasing force of contraction in failing (by ∼100%) than in nonfailing cardiac preparations (by ∼500%). With isoprenaline, cAMP content was ∼50% lower in failing than in nonfailing preparations. We conclude that the reduced increase in force of contraction of failing human cardiac preparations with isoprenaline added may be causally related to an inadequately increased cAMP content.