N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a “remarkable predictor” of incident atrial fibrillation (AF), even after adjustment for other known risk factors, according to the results of a new study.
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Reporting their findings (Circulation 2009;120:1768-74), a team led by Dr Kristen Patton (University of Washington, Seattle, US) conclude that: “Our results indicate a compelling, graded association between NT-proBNP levels and AF in a large, diverse cohort with extensive follow-up. The fact that elevated baseline NT-proBNP levels predict a diagnosis of AF even 16 years later suggests that peptide elevations precede the onset of arrhythmia,” they add.
BNP, a neurohormone produced by the heart, regulates cardiac function and is widely used as a marker of heart failure. The precursor protein pro-B-type natriuretic peptide is cleaved to form BNP and the amino terminal NT-proBNP; both of these circulate in the plasma.
A previous study using Framingham data has also shown elevated BNP levels to be predictive of AF but only 68 subjects developed AF during the study. The current study, however, analysed data from 5,445 men and women over 65 years of age participating in the Cardiovascular Health Study, in which there were 1,126 cases of incident AF. Among those with the highest levels of NT-proBNP, there was a four-fold increase in the risk of incident AF compared with individuals with the lowest levels.
In the current study, NT-proBNP remained the strongest predictor of incident AF after adjustment for other variables, including age, sex, medication use, blood pressure, echocardiographic variables, diabetes mellitus, and heart failure.
The authors note that little is known about the potential electrophysiological effects of BNP, but they speculate that it may have similar properties to atrial natriuretic peptide which has been shown to affect the sodium, calcium and potassium channels and increase the cardiac pacemaker current.