Stem cells transplantations might offer new treatment options for patients suffering from ischemic heart disease. However, the effectiveness of such a therapy in chronic heart failure and the most efficient cell type are still not well-defined. Therefore, we conducted an hemodynamic comparison of bone marrow mononuclear cells (BMMC) and mesenchymal stem cells (MSC) transplantation in a large animal model of chronic myocardial infarction. Eight weeks after coronary ligation, 24 dogs were randomly assigned in 3 groups: placebo, BMMC, and MSC. Hemodynamic assessment was performed one week before and 8 weeks after cells or medium injection. Cardiac output was decreased 8 weeks after therapy or placebo (p<0.001). The abnormally high left ventricular end diastolic pressure (LVPd) stayed unchanged while end diastolic left ventricular volume (LVEDV) was decreased 8 weeks after cellular or medium injection (P<0.05), leading to a decrease of the LVEDV/LVPd ratio. Heart rate, arterial elastance, dP/dtmax, ejection fraction, the left ventricular time constant of isovolumic pressure drop and dP/dtmin

stayed unchanged after treatment. The fall of global cardiac performance could be at least partially attributed to the decreased LVEDV, result of the lowered preload. The low LVEDV/LVPd ratio could be secondary to a decrease in left ventricular compliance as a consequence of myocardial remodelling. With this method used, we found no effect of intramyocardial injection of bone marrow stem cells on global left ventricular function. However, these results have to be completed by the measurements of left ventricular end-systolic elastance, as a load independent variable of contractility, and of the ventricular arterial coupling.