Aims: To assess the role of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in the diagnosis of major structural heart disease (MSHD) in patients with atrial fibrillation (AF) compared with those with sinus rhythm (SR) using receiver operator characteristic (ROC) analysis. NT-proBNP is elevated in MSHD and heart failure (HF). AF, a common finding in HF and MSHD, is also associated with raised plasma NT-proBNP. As a result, the utility of NT-proBNP for predicting MSHD may be reduced.
Methods and results: One thousand four hundred and seventy-six patients underwent assessment at a single centre, performed without the knowledge of NT-proBNP levels. MSHD included left ventricular (LV) systolic and diastolic dysfunctions, left-sided valvular disease, right heart disease (including pulmonary hypertension) and severe LV hypertrophy. One hundred and fifty-five patients were excluded due to renal impairment, atrial flutter, or a pacemaker. Seven hundred and ninety-three patients were diagnosed with MSHD. Median NT-proBNP concentrations for patients with MSHD were 960 (IQR 359-2625) pg/mL and 2491 (1443-4368) pg/mL for SR (n = 591) and AF (n = 202), respectively (P < 0.001). Patients without MSHD had NT-proBNP levels of 179 (90-401) pg/mL and 1000 (659-1760) pg/mL for SR (n = 454) and AF (n = 74), respectively (P < 0.001). The area under the ROC curve for NT-proBNP to detect MSHD was 0.79 for SR (95% CI 0.77-0.82) and 0.78 for AF (95% CI 0.72-0.84). NT-proBNP cut-off levels necessary to achieve a 1 in 100 false negative rate were 27.5 (7.5-30.5) pg/ml and 524 (253-662) pg/ml for SR and AF, respectively.
Conclusion: NT-proBNP performs as well in patients with SR as in those with AF. However, significantly higher cut-off levels are required for patients with AF to achieve similar levels of diagnostic specificity.