ACE2 and heart failure: In the acute phase, the serum Ang-(1-7) concentration was statistically significantly lower and the serum ACE2 concentration was statistically significantly higher in heart failure patients than the healthy individuals (2.40 ± 1.11 vs. 3.10 ± 1.10 ng/ml, P<0.005 and 7.45 ± 3.13 vs. 4.84 ± 2.25 ng/ml, P<0.005, respectively; Figures 2 and 3).