NPPB and Arrhythmia: Therefore, other markers must be taken into account, such as (a) the presence of symptoms, (b) a pathological electrocardiographic pattern, (c) the presence of arrhythmias during Holter monitoring, (d) increased biomarker levels (especially N-terminal prohormone of brain natriuretic peptide - NT-proBNP) or (e) a lack of significant improvement in the LV ejection fraction during exercise [11,21].