Atrial fibrillation and biomarkers of myocardial fibrosis in heart failure

Objectives. Alterations of collagen metabolism present in heart failure promote the fibrotic substrate for the development of atrial fibrillation (AF). Myocardial collagen I synthesis and degradation can be assessed indirectly by circulating biomarkers such as the carboxy terminal propeptide (PICP) and carboxy-terminal telopeptide (CITP), respectively. Design. We examined myocardial collagen type-I metabolism in 143 patients with systolic heart failure (New York Heart Association Class 2–4) in relation to coexisting AF. Results. Mean age was 75 years, blood pressure 134/80 mm Hg, ejection fraction 34%, serum PICP 81 μg/L and CITP 8.3 μg/L, and median plasma brain natriuretic peptide 215 pg/L; 77 were in AF. PICP and CITP were related to left atrial diameter (r = 0.22, P = 0.013, and r = 0.26, P = 0.003) and CITP to pulmonary capillary wedge pressure and C-reactive protein (r = 0.19, P = 0.044, and r = 0.29, P = 0.003). A logistic regression suggested that PICP (odds ratio per 1 μg/L change 1.01, P = 0.012) and left ventricular end-diastolic volume (odds ratio per 1 mL change 0.98, P < 0.001) were independently associated with coexisting AF. Conclusion. Collagen type-I metabolism is associated to left atrial size. Heart failure patients with coexisting AF exhibit more altered collagen type-I metabolism than patients in sinus rhythm. This might represent more severe atrial and ventricular fibrosis.