Figure 1. Box plot of plasma NT-proBNP concentrations in AECB patients with or without LV failure.
Horizontal lines in the box indicate 25th, 50th and 75th percentiles, and I bars represent highest and lowest values. NT-proBNP: N-terminal pro-B type natriuretic peptide; AECB: acute exacerbation of chronic bronchitis; LV: left ventricular.