Plasma NT-proANP in patients with persistent atrial fibrillation who underwent successful cardioversion.

Background: Atrial fibrillation (AF) decreases quality of life and significantly increases risk of stroke, congestive heart failure and death. Atrial overload and stretch also result in increased production of natriuretic peptide type A (ANP). The biologically inactive prohormone NT-proANP is released to plasma in the same amounts as ANP but it has higher levels in the blood due to decreased degradation in vivo. In vitro degradation is also slower and NT-proANP may be an interesting alternative for ANP.
Aim: To evaluate NT-proANP plasma concentration in patients with persistent AF following successful cardioversion.
Methods: The study group consisted of 43 patients with persistent AF and normal left ventricular systolic function, who underwent successful electrical cardioversion (EC). The control group comprised 20 patients with sinus rhythm without a history of AF. Blood samples were collected twice, during visits 24 h before and after EC. All patients were also examined 30 days after the sinus rhythm recovery. The NT-proANP concentration was measured using an immunochemical method (ELISA).
Results: Plasma NT-proANP concentration was significantly increased in patients with persistent AF compared to the control group (4.8 +/- 2.9 vs. 2.8 +/- 1.2 nmol/l, p = 0.004). Plasma NT-proANP level decreased significantly after successful cardioversion (to 3.2 +/- 2.4 nmol/l; p < 0.0001). There was no correlation between the baseline NT-proANP concentration and sinus rhythm maintenance during 30 days after EC.
Conclusions: Plasma NT-proANP concentration is higher in patients with persistent AF and normal left ventricular systolic function than in patients without arrhythmia. Sinus rhythm recovery due to EC leads to a decrease of plasma NT-proANP. The baseline NT-proANP level has no prognostic value for prediction of sinus rhythm maintenance during 30 days after EC.