ACE2 and heart failure: Serum ACE2 activity was higher in hypertensive patients compared to healthy individuals (hypertensive: 24.8±0.9 UF/mL, healthy: 16.2±0.8 UF/mL; P<0.0001, Figure 4A) and further increased in HF patients (HF – CRT before: 42.5±2.9 UF/mL; P<0.0001, Figure 4A), suggesting that sACE2 activity may be a biomarker of cardiovascular disease or imminent heart failure.