Background : The level of natriuretic peptide (NP) is high in atrial fibrillation (AF) and may decrease after cardioversion to sinus rhythm. The levels of atrial NP (ANP) and brain NP (BNP) in different types of AF and whether ANP and BNP have predictive values for relapsed AF have not been determined.
Methods and Results : ANP and BNP were measured in 100 consecutive patients with AF but without heart dysfunction at baseline and in 20 controls. All patients had higher levels than controls (p<0.01). After cardioversion treatment with antiarrhythmic therapy, 40 patients still showed AF, whereas 60 patients showed sinus rhythm. ANP and BNP levels decreased significantly after cardioversion (163.55±54.27pg/mlvs. 200.20±55.63pg/ml; 124.15±43.00pg/ml vs. 161.99±48.04pg/ml, respectively, both p<0.0001). During 500-day follow-up, AF relapsed in 16 patients in the successful cardipversion group as compared with 42 patients who remained sinus rhythm with the 42 patients, the 16 patients showed higher concentrations of ANP (187.72±32.79pg/ml vs. 138.42±30.65pg/ml, p<0.0001). The area under the receiver-operating characteristic curve was 0.799 for BNP and 0.706 for ANP in predicting a relapse of AF. Using the BNP optimized cut-off level of 138 pg/ml, relapsed AF can be predicted with relatively acceptable accuracy.
Conclusions : ANP and BNP levels decrease significantly after cardioversion in patients with AF, and the levels of the two can be useful predictors of relapsed AF.