title: Atrium as a source of brain natriuretic polypeptide in patients with atrial fibrillation.
abstract: BACKGROUND
  Plasma brain natriuretic polypeptide (BNP) levels have been used as biochemical markers of systolic left ventricular (LV) dysfunction. Although in vitro studies have shown the existence of BNP messenger RNA in the atria, the main production site of BNP is believed to be the ventricle. The hypothesis that the atrium could be a source of BNP was examined in patients with lone atrial fibrillation (AF), the most common type of sustained arrhythmia.
  
  
  RESULTS
  We studied 16 controls and 21 patients with lone AF. Plasma samples for BNP were selectively and serially obtained from the aorta, anterior interventricular vein (AIV), and coronary sinus (CS). Atrial natriuretic polypeptide (ANP) levels were also measured to determine whether the CS samples contained significant amounts of atrial venous drainage. Of the 3 sample locations, the CS had the greatest ANP levels, confirming transcatheter sampling position accuracy. BNP levels were significantly greater in the CS than AIV in the patients with AF (279 +/- 226 v 126 +/- 97 pg/mL; P < .01). Consequently, plasma BNP levels were also greater in the patients with AF than controls (103 +/- 90 v 5 +/- 2 pg/mL; P < .001). LV ejection fraction was significantly less in patients with AF than control patients. Atrial production of BNP decreased significantly after successful DC cardioversion of AF in the 5 restudied patients (182 +/- 139 v 59 +/- 64 pg/mL; P < .05).
  
  
  CONCLUSIONS
  The data suggest that AF is a condition in which BNP is produced in the atrium itself.
authors.affiliation: The Fourth Department of Internal Medicine, Shimane Medical University, Izumo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Murakami
authors.forename: K
authors.initials: K
authors.lastname: Sano
authors.forename: H
authors.initials: H
authors.lastname: Katoh
authors.forename: T
authors.initials: T
authors.lastname: Shimada
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood* / Q000503:physiopathology / Q000628:therapy; D009320:Atrial Natriuretic Factor / Q000097:blood; D015415:Biomarkers / Q000097:blood; D006328:Cardiac Catheterization; D004554:Electric Countershock; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000378:metabolism*; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood* / Q000235:genetics; D011863:Radioimmunoassay; D013318:Stroke Volume
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor