Figure 3.

Plasma renin activity concentration (PRAC) in healthy control and heart failure (HF) patients with systolic dysfunction: (A) Plasma samples of healthy control patients (normal ejection fraction, EF) and patients with reduced (rEF) with and without symptomatic HFrEF. (B) Spearman correlation of PRAC to plasma N-terminal pro-atrial natriuretic peptide (N-ANP). All patients were males and 50–70 years old. Groups were healthy control subjects (n = 16), HF with reduced ejection fraction (HFrEF) asymptomatic (n = 16), and HFrEF symptomatic (n = 15). Venous blood samples were collected using EDTA-aprotinin tubes. This investigation was a part of our previously reported study [25]. This study was approved by the Institutional Review Board, and all subjects gave their informed consent for inclusion before they participated in this study [25]. Data represent mean ± SEM. ++ p < 0.01, (red, Control vs. Asymptomatic) +++ p < 0.0001 (black, Control vs. Symptomatic), * p < 0.05 (Asymptomatic vs. Symptomatic HFrEF). AU = arbitrary units. Comparisons between groups were calculated using the Mann–Whitney test. Statistical analysis was performed with GraphPad Prism 8.0.2 (GraphPad Software, San Diego, CA, USA). p > 0.05 was considered significant.