Atrial Fibrillation and Amino-Terminal Pro-Brain Natriuretic Peptide
Atrial Fibrillation and Amino-Terminal Pro-Brain Natriuretic Peptide
Background: Amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing is useful for diagnosis or exclusion of heart failure (HF) in dyspneic patients. Atrial fibrillation (AF) may cause dyspnea in the absence of acute HF and may also affect plasma levels of NT-proBNP.
Methods: We prospectively enrolled 599 patients presenting with dyspnea to the emergency department and obtained a blood sample for NT-proBNP measurement. The diagnosis of AF was identified via presentation electrocardiogram. A final diagnosis of HF was determined by blinded study physicians using all available hospital records for each subject through 60 days of follow-up. We assessed the association between the presence of AF and level of NT-proBNP in subsets of patients with and without HF.
Results: Of 599 dyspneic patients, 75 (13%) were in AF at presentation; these patients had significantly higher median NT-proBNP levels when compared with those without AF (2934 vs 294 pg/mL, P < .0001). Among patients with acute HF, AF was present in 28%; NT-proBNP levels were lower in those with AF versus those without (3488 vs 4492 pg/mL, P < .001), but AF was not independently associated with NT-proBNP after multivariable adjustment. In patients without acute HF, median NT-proBNP concentrations were significantly higher in those with AF than in those without (932 vs 121 pg/mL, P = .02); in these subjects, AF was the strongest predictor of an NT-proBNP concentration in a range consistent with acute HF (odds ratio 9.94, 95% CI 2.97-33.3, P < .001).
Conclusion: Atrial fibrillation is associated with higher NT-proBNP concentrations in dyspneic patients, particularly in those without acute HF.
Securing a correct diagnosis of acute heart failure (HF) in patients presenting with dyspnea to an emergency department (ED) can be challenging. Released as a consequence of myocardial wall stress, and generated as a cleavage product of a 108-amino acid intracellular precursor (proBNP108), amino-terminal pro-brain natriuretic peptide (NT-proBNP) is a 76-amino acid peptide whose measurement has been shown to be useful for diagnosis and risk stratification of dyspneic patients with and without acute HF. The recent N-terminal PRIDE and ICON studies have provided a framework for the interpretation of NT-proBNP concentrations. However, a growing understanding of natriuretic peptides has led to the recognition of the wide variety of circumstances other than acute HF in which NT-proBNP is elevated, such as acute coronary syndromes (ACSs) or pulmonary embolism (PE). Accordingly, to optimally use NT-proBNP in the clinical setting, better understanding of medical illnesses that may influence the diagnostic accuracy of this marker is necessary to avoid inappropriate diagnosis of acute HF.
Atrial fibrillation (AF) is common, and it may lead to dyspnea in the absence of acute HF, but is also a frequent comorbidity in patients with acute HF. Recently, there has been evidence to suggest a positive correlation between NT-proBNP concentrations and the presence of AF in the absence of clinical HF. In addition, concentrations of the related peptide BNP were recently noted to be significantly higher in dyspneic subjects with AF in the Breathing Not Properly Multinational Study, even in the absence of a clinical diagnosis of acute HF. On the basis of these observations, we hypothesized that AF alone might similarly be associated with an elevated NT-proBNP level, even in subjects without HF.
Abstract and Introduction
Abstract
Background: Amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing is useful for diagnosis or exclusion of heart failure (HF) in dyspneic patients. Atrial fibrillation (AF) may cause dyspnea in the absence of acute HF and may also affect plasma levels of NT-proBNP.
Methods: We prospectively enrolled 599 patients presenting with dyspnea to the emergency department and obtained a blood sample for NT-proBNP measurement. The diagnosis of AF was identified via presentation electrocardiogram. A final diagnosis of HF was determined by blinded study physicians using all available hospital records for each subject through 60 days of follow-up. We assessed the association between the presence of AF and level of NT-proBNP in subsets of patients with and without HF.
Results: Of 599 dyspneic patients, 75 (13%) were in AF at presentation; these patients had significantly higher median NT-proBNP levels when compared with those without AF (2934 vs 294 pg/mL, P < .0001). Among patients with acute HF, AF was present in 28%; NT-proBNP levels were lower in those with AF versus those without (3488 vs 4492 pg/mL, P < .001), but AF was not independently associated with NT-proBNP after multivariable adjustment. In patients without acute HF, median NT-proBNP concentrations were significantly higher in those with AF than in those without (932 vs 121 pg/mL, P = .02); in these subjects, AF was the strongest predictor of an NT-proBNP concentration in a range consistent with acute HF (odds ratio 9.94, 95% CI 2.97-33.3, P < .001).
Conclusion: Atrial fibrillation is associated with higher NT-proBNP concentrations in dyspneic patients, particularly in those without acute HF.
Introduction
Securing a correct diagnosis of acute heart failure (HF) in patients presenting with dyspnea to an emergency department (ED) can be challenging. Released as a consequence of myocardial wall stress, and generated as a cleavage product of a 108-amino acid intracellular precursor (proBNP108), amino-terminal pro-brain natriuretic peptide (NT-proBNP) is a 76-amino acid peptide whose measurement has been shown to be useful for diagnosis and risk stratification of dyspneic patients with and without acute HF. The recent N-terminal PRIDE and ICON studies have provided a framework for the interpretation of NT-proBNP concentrations. However, a growing understanding of natriuretic peptides has led to the recognition of the wide variety of circumstances other than acute HF in which NT-proBNP is elevated, such as acute coronary syndromes (ACSs) or pulmonary embolism (PE). Accordingly, to optimally use NT-proBNP in the clinical setting, better understanding of medical illnesses that may influence the diagnostic accuracy of this marker is necessary to avoid inappropriate diagnosis of acute HF.
Atrial fibrillation (AF) is common, and it may lead to dyspnea in the absence of acute HF, but is also a frequent comorbidity in patients with acute HF. Recently, there has been evidence to suggest a positive correlation between NT-proBNP concentrations and the presence of AF in the absence of clinical HF. In addition, concentrations of the related peptide BNP were recently noted to be significantly higher in dyspneic subjects with AF in the Breathing Not Properly Multinational Study, even in the absence of a clinical diagnosis of acute HF. On the basis of these observations, we hypothesized that AF alone might similarly be associated with an elevated NT-proBNP level, even in subjects without HF.