Cardiac myosin‐binding protein C as a candidate biomarker in heart failure: rational but not revolutionary

Biomarkers have become a well-established part of the diagnosis and management of heart failure (HF). The natriuretic peptides, particularly B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), are endorsed by all authoritative guidelines as a highly recommended aid in the diagnosis of acute HF (AHF).1,2 They are reflective of intra-cardiac haemodynamic load. Their widespread application has made a major impact on clinical decision-making in both acute and chronic HF worldwide. Their best proven use is in the timely distinction of AHF among patients presenting with new onset of shortness of breath. In addition, plasma concentrations of cardiac troponins, T and I, now both measurable by highly sensitive assays, provide a semi-quantitative estimate of the extent of ongoing cardiomyocyte injury in HF and give independent prognostic information in both acute and chronic HF.3 However, these existing tools, though providing considerable power to rule out AHF, have imperfect positive predictive diagnostic value, which for NT-proBNP sits at about 70%, in distinguishing AHF from other causes of recent onset dyspnoea.3 Furthermore, despite consistent reports suggesting that plasma natriuretic peptides and cardiac troponins are independently predictive of important clinical outcomes in acute and chronic HF, the best comprehensive multivariable models incorporating these markers still offer no more than modest prognostic accuracy or precision with receiver operator-derived c statistics seldom exceeding 0.75. Hence discovery, assessment and validation of alternative or additional markers remains necessary. In this issue of the Journal, Kozhuharov et al.4 provide a powerful assessment of the diagnostic and prognostic performance of an attractive candidate marker in AHF, cardiac myosin-binding protein