NPPB and heart failure: The definition of heart failure was based on the following: 1) symptoms or signs of heart failure (e.g., dyspnea, palpitations, fatigue, and edema, among others); 2) LVEF < 50%; and 3) NT-proBNP > 450 ng/L (<50 years), >900 ng/L (50–75 years), and >1,800 ng/L (>75 years) (9).