Abstract: AIM:To investigate the correlation between heart rate variability and brain natriuretic peptide (BNP) in patients with persistent atrial fibrillation (AF). METHODS: Forty-five patients with persistent AF were placed into one group and 20 patients without persistent AF were placed in the normal control group. Twenty-four hour ECG was monitored for the time domain indexes of heart rate variability, and plasma BNP concentration was tested. Correlation between the time domain indexes and plasma BNP concentration was analyzed. RESULTS: In patients with persistent AF, the heart rate increased and heart rate variability time domain indexes (SDNN, RMSSD and PNN50) increased significantly (P<0.01). The actual RINNT was negatively correlated with plasma BNP concentration. After correction with the average heart rate, heart rate variability time domain indexes (RMSSDDdiff and PNN50Ddiff) were positively correlated with BNP concentration. CONCLUSION: In patients with persistent AF, the time domain parameters of heart rate variability increase and plasma BNP concentration is affected by the heart rate and the changes in heart rate variability.