NT-proBNP cut-off value for ruling out heart failure in atrial fibrillation patients - A prospective clinical study

Study objective: N-terminal pro-brain natriuretic peptide (NT-proBNP) measurements can be used to rule out heart failure in patients with sinus rhythm. Atrial fibrillation often coexists with heart failure but affects NT-proBNP levels. This study aims to identify the optimal NT-proBNP cut-off value for ruling out heart failure among atrial fibrillation patients.

Methods: This prospective study included 409 atrial fibrillation patients admitted to the emergency department. The inclusion criterion was documented atrial fibrillation on a 12‑lead electrocardiogram. All patients completed a NT-proBNP blood sample, a chest X-ray and an echocardiogram. Heart failure was defined as a left ventricular ejection fraction of <40%.

Results: In total, 409 patients were included (mean age: 75.2 ± 11.6). The median NT-proBNP level was 2577 ng/L (quartiles: 1185-5438) and 21% had heart failure. We found a lower median NT proBNP level of 3187 ± 3973 ng/L in patients without heart failure compared to 9254 ± 8008 ng/L in patients with heart failure (absolute difference: 4131, 95% (CI): 3299-4986, p < 0.001). The area under the receiver operating characteristic curve for diagnosing heart failure was 0.82 (95% confidence interval: 0.77-0.87). The optimal cut-off value for ruling out heart failure was 739 ng/L with a sensitivity of 99%, a specificity of 18%, and a negative predictive value of 98%.

Conclusions: NT-proBNP can be used to rule out heart failure in atrial fibrillation patients with a high negative predictive value, but low specificity.

Trial registration number: NCT04125966. https://clinicaltrials.gov/ct2/show/NCT04125966.