NT-proANP levels in peripheral and cardiac circulation

Background Recent studies have reported an association between N-terminal atrial natriuretic peptide (NT-proANP) and the progression of atrial fibrillation (AF). However, NT-proANP levels in peripheral and cardiac circulation in AF patients and in non-AF individuals need to be defined. The aims of the current study are (1) to analyze NT-proANP levels in peripheral and cardiac circulation in AF patients and (2) to compare NT-proANP levels in individuals with and without AF. Methods We recruited AF patients who were undergoing their first AF catheter ablation and non-AF individuals. Blood plasma samples taken from the femoral vein and the left atrium (LA) were collected before AF ablation in the AF patients and from the cubital vein in the non-AF controls. Low voltage areas (LVAs) were determined using high-density maps during catheter ablation and defined as < 0.5 mV. Results The study included 189 AF patients (64 +/- 10 years, 59% male, 61% persistent AF, 30% LVAs) and 26 non-AF individuals (58 +/- 10 years, 50% male). Patients with AF were significantly older and had larger LA (p < 0.05). Compared to non-AF controls, peripheral and cardiac NT-proANP levels were significantly higher in AF patients without and with LVAs (median 5.4, 10.5, 14.8 ng/ml, respectively, p < 0.001). In multivariable analysis, NT-proANP (OR 1.238, 95% CI 1.007-1.521, p = 0.043) remained significantly different between non-AF individuals and AF patients. In AF, NT-proANP levels were significantly higher in the cardiac blood samples than in the peripheral blood (median 13.0 versus 11.4 ng/ml, p = 0.003). The ability to predict LVAs was modest when using cardiac NT-proANP (AUC 0.661) and peripheral NT-proANP (AUC 0.635), without statistical difference (p = 0.937). Conclusions NT-proANP levels are higher in individuals with AF than in controls and are more pronounced in progressed AF. Elevated cardiac and peripheral NT-proANP levels similarly predict LVAs.