Heart Failure in Humans Reduces Contractile Force in Myocardium From Both Ventricles

This study measured how heart failure affects the contractile properties of the human myocardium from the left and right ventricles. The data showed that maximum force and maximum power were reduced by approximately 30% in multicellular preparations from both ventricles, possibly because of ventricular remodeling (e.g., cellular disarray and/or excess fibrosis). Heart failure increased the calcium (Ca(2+)) sensitivity of contraction in both ventricles, but the effect was bigger in right ventricular samples. The changes in Ca(2+) sensitivity were associated with ventricle-specific changes in the phosphorylation of troponin I, which indicated that adrenergic stimulation might induce different effects in the left and right ventricles.