Subcutaneous injection of high doses of recombinant IL-6 in wild-type rats induces a dose-dependent dilatation of the left ventricle leading to heart failure within 7 days (Janssen et al., 2005), whereas continuous infusion of a lower doses of IL-6 in rats leads to ventricular hypertrophy and fibrosis (Meléndez et al., 2010). Here, IL6 is linked to cardiac hypertrophy.