Objective As shown previously in patients with new-onset atrial
fibrillation (AF) without symptoms or signs of heart failure, N-terminal
pro-brain natriuretic peptide (NTproBNP) increases rapidly, reaching a
maximum within 24-36 h, and then decreases even if AF persists. A study
was undertaken to use NTproBNP measurements in patients with AF of
unknown time of onset to identify patients with presumed recent onset of
the arrhythmia.
Design Two-group open cross-sectional study.
Setting Hospitalised patients in cardiology departments of four
hospitals.
Patients Patients presenting with AF of unknown onset and no signs or
symptoms of heart failure were separated into two groups: group A with
NTproBNP above the cut-off level and group B with a low NTproBNP level.
Interventions No therapeutic intervention. All patients underwent
transoesophageal echocardiography (TEE).
Main outcome measures Presence of left atrial thrombus on TEE.
Results In group A (N=43) only two patients (4.7%) were found to have
an atrial thrombus on TEE (negative predictive value of raised NTproBNP
levels 95.3%) compared with 13 of 43 patients in group B (30.2%;
p=0.002). Patients with a higher CHA(2)DS(2)VASc score (p=0.002) and a
larger left atrium (p < 0.001) were more likely to have an atrial
thrombus. In the multivariate analysis, NTproBNP below the cut-off level
was the most powerful predictor of the presence of thrombus (OR 25.0;
p=0.016).
Conclusion The reported strong correlation between raised NTproBNP
levels and the absence of atrial thrombi on TEE suggests that the
short-term increase in NTproBNP levels after AF onset might be used to
assess the age of the arrhythmia and thus the safety of cardioversion in
patients with AF of unknown onset and no heart failure