NTproBNP levels may predict timing of AF onset
MedWire News: Measuring N-terminal pro brain natriuretic peptide (NTproBNP) levels in patients with atrial fibrillation (AF) of unknown onset may help to determine the age of the arrhythmia, according to Greek researchers.
"If a patient presenting with AF of unknown time of onset has markedly raised NTproBNP levels in the absence of heart failure (HF) symptoms and signs, it may mean that the arrhythmia is not more than 36-48 hours old," explain Georgios Giannopoulos (Athens General Hospital) and team.
The researchers observed the frequency of atrial thrombi in 86 patients with AF of unknown onset and found a strong correlation between elevated NTproBNP levels and the absence of atrial thrombi.
This association, say Giannopoulos and team, suggests that measuring NTproBNP levels provides an effective method for identifying AF patients with low thromboembolic risk who "are therefore safe for immediate cardioversion."
As reported in the journal Heart, the researchers arranged all patients into two groups according to NTproBNP levels; group A (n=43; NTproBNP above cut-off for normal [>450, 900, and 1800 pg/ml for patients aged <50, 50-75, and >75 years, respectively]) and group B (n=43; NTproBNP below cut-off).
Atrial thrombi, determined by transesophageal echocardiogram (TEE), occurred more frequently among the patients with NTproBNP levels below the cut-off than in those with levels above the cut-off, at 30.2% versus 4.7%.
After adjustment for multiple variables, such as age and comorbidity, a NTproBNP level below the cut-off was associated with a 25-fold higher risk for atrial thrombus compared with a NTproBNP level above the cut-off (p-0.016).
Furthermore, Giannopoulos and colleagues report that atrial thrombus risk positively correlated with the AF stroke risk CHA2DS2VASc (Congestive heart failure, Hypertension, Age >65, Stroke/TIA/thromboembolism, VAScular disease, diabetes mellitus, female) score, and left atrium (LA) size (on transthoracic echocardiogram; p=0.023, p=0.029, respectively).
They therefore conclude: "A combination of NTproBNP levels (to assess the time frame of AF onset) with LA size and CHA2DS2VASc score might be able to identify correctly almost all patients without thrombi and who are therefore safe for immediate cardioversion."
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By Lauretta Ihonor