OBJECTIVE: Cardiac secretion of brain natriuretic peptide (BNP) increases with 
the progression of congestive heart failure (CHF). The plasma measurement of BNP 
emerged recently as a useful, cost-effective biomarker for the diagnosis and 
prognosis of CHF.
METHODS: BNP assay is useful for evaluating patients with acute dyspnea, because 
a low level can help rule out CHF in primary care settings and reduce the demand 
for echocardiography. Equally, BNP level can be particularly useful in 
recognizing heart failure in a patient with acute dyspnea and a history of 
chronic obstructive pulmonary disease.
RESULTS: However, although the clinical use of BNP as a biomarker in CHF is 
increasing, the specificity of BNP in CHF is not strong, suggesting that other 
mechanisms beyond simple ventricular stretch stimulate BNP release. Multiple 
disorders in the intensive care unit, apart from CHF, cause elevated BNP levels, 
including cardiovascular disease states such as ischemia, arrhythmias, cardiac 
hypertrophy, and coronary endothelial dysfunction, as well as disorders of no 
cardiac origin, such as sepsis, septic shock, and acute respiratory distress 
syndrome. Moreover, the impact of increased BNP in patients with sepsis is not 
clear. The relationship between BNP and both left ventricular ejection fraction 
and left-sided filling pressures is weak, and data on the prognostic impact of 
high BNP levels in patients with sepsis are conflicting.
CONCLUSION: Nevertheless, this review highlights the potential benefits of BNP 
in the recognition and management of heart failure, and defines the gray zones 
of BNP levels; it also identifies conditions influencing BNP levels in relation 
to a certain heart failure and describes conditions of no cardiac origin with 
increased BNP.