Effects of exercise testing on natriuretic peptide secretion in patients with atrial fibrillation.

BACKGROUND: Assessment of endocrine profile in patients with cardiovascular diseases has become increasingly important during the last decade. Plasma brain natriuretic peptide (BNP) levels have been used as a marker of left ventricular dysfunction. However, the role of BNP in patients with atrial fibrillation (AF) and normal left ventricular function has not yet been determined.

AIM: To examine changes in the secretion of natriuretic peptides (atrial natriuretic peptide - ANP and BNP) during exercise in patients with persistent or permanent AF.

METHODS: The study group consisted of 42 patients with permanent AF and 77 patients with persistent AF. There were no significant differences in baseline clinical (except AF duration), echocardiographic and haemodynamic data between the groups. The control group comprised 20 patients. All had normal sinus rhytm without a history of AF and were compatible in age, gender and concomitant diseases with the examined groups. The ANP and BNP samples were obtained at rest and at the peak of the exercise testing. Duration of exercise testing was 10 min.

RESULTS: The multiple regression analysis showed an association between ANP levels and left atrial volume (p = 0.0001), maximal heart rate (p = 0.0036) and NYHA class (p < 0.0001). There was a trend toward a significant relation between AF duration and ANP levels. There was a significant correlation between BNP levels and heart failure class according to NYHA (p < 0.0001). A significant and strong positive correlation of ANP and BNP concentrations at rest was observed in all groups of AF. Significant variation of natriuretic peptide release in response to exercise (ANPex and BNPex) was observed. The highest increase of ANP level and the lowest increase of BNP level were noted in the control group, and no significant differences were found in ANP and BNP secretion between the groups with persistent and permanent AF.

CONCLUSIONS: Neurohormonal response to exercise differs between patients with AF and those in sinus rhythm. Exercise testing may be used to assess the ability of cardiac myocytes to increase peptide secretion.