It has been reported that plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) level increase in the patients with atrial fibrillation (af). However, it is not clear how the plasma ANP and BNP level increase in the patients with paroxysmal af (Paf). We hypothesized that pressure overload of left atria would induce paroxysmal atrial fibrillation and may cause to increase plasma ANP and BNP level.

Method: 39 patients (23 men, age 68 ± 10 y.o; mean ± SD) with paf were measured plasma ANP and BNP levels before and consecutive 5 days after conversion to sinus rhythm by using antiarrhythmic drugs or electrical cardioversion, and trans-mitral flow was measured to evluate A/E ration as an index of left atrial function at day 7 after conversion.

Results: 13 patients recurred paf (R-group) and 26 patients maintained sinus rhythm (S-group) within 1 month after conversion. The duration of paf was significantly longer in R-group than in S-group ( median time; 91 vs 18 hour, p<0.05). Plasma ANP and BNP level were significantly decreased 24 hours after cardioversion than those of during af in both groups. In S-group, plasma BNP level was significantly decreased following 5 days after conversion. However, in R-group, ANP and BNP levels were significantly increased before recurrence of paf (data taken on day 5 after conversion from the patients without recurrence and on the last day of sinus rhythm from patients with recurrence of af, within 5 days after conversion). In R-group (six patients were excluded to evaluate A/E ration because they recurred paf before to measure echocardiography), patients showed significantly lower A/E ratio than that of in S-group (0.5 ± 0.2 vs 1.2 ± 0.6, p<0.001).

Conclusion: This is first report to show that preceding increase of plasma ANP and BNP levels before recurrence of paf. These data suggest that pressure overload would be occurred during sinus rhythm, which may provoke to increase of plasma ANP and BNP levels and may trigger of paf.