Because humoral alterations have been implicated in the generation and perpetuation
of atrial fibrillation (AF), we aimed to elucidate possible abnormalities in atrial
endocrine function in the setting of lone AF. Levels of plasma apelin and amino terminal
fragment of the brain natriuretic peptide prohormone (NT-pro-BNP) were measured in
40 patients with persistent AF, before and 1 month after electrical cardioversion,
and in 15 controls in sinus rhythm (SR). All patients were successfully cardioverted
to SR, although in 9 of them AF recurred. Baseline apelin levels were lower and NT-pro-BNP
levels higher in patients with AF compared to controls (380 +/- 186 vs 700 +/- 151
pg/ml, p <0.001, and 615 +/- 611 vs 50 +/- 28 pg/ml, p <0.001, respectively). Maintenance
of SR resulted in an increase of apelin and a decrease of NT-pro-BNP levels during
the postcardioversion follow-up period compared to baseline (497 +/- 170 vs 368 +/-
178 pg/ml, p <0.001, and 206 +/- 106 vs 398 +/- 269 pg/ml, p <0.001 respectively).
Patients who developed AF recurrence by the end of the follow-up period had similar
values of apelin and NT-pro-BNP on final and initial evaluations (444 +/- 142 vs 422
+/- 217 pg/ml, p = 0.62, and 1,328 +/- 714 vs 1,362 +/- 862 pg/ml, p = 0.74, respectively).
Stepwise logistic regression analysis showed that left atrial diameter (b =-0.49,
p = 0.05), and baseline NT-pro-BNP (b = 0.006, p = 0.022), but not apelin, were independent
predictors for AF recurrence. In conclusion, this study suggests that endocrine heart
function, as judged from apelin and NT-pro-BNP levels, is reversibly modified in the
setting of lone AF. This could influence systemic hemodynamics and pharmacologic measures
designed to treat this arrhythmia.