Assessment of N-terminal pro-brain natriuretic peptide in patients with arrhythmia due to undifferentiated connective tissue disease

Aim. To study the relationship between the level of N-terminal pro-brain natriuretic peptide (NT-proBNP) and myocardial abnormalities in patients with cardiac arrhythmias due to undifferentiated connective tissue disease (UCTD). Material and methods. This cross-sectional comparative study included young and middle-aged patients with arrhythmias due to UCTD: group 1 (18-44 years old, n=127), group 3 (45-59 years old, n=10). The control groups (n=30, group 2; n=8, group 4) included volunteers with single phenotypic signs of UCTD, comparable in age and sex. A standard clinical examination, 72-hour electrocardiographic monitoring, Speckletracking echocardiography, and NT-proBNP level assessment were performed. Results. In patients of groups 1 and 3, a significant increase in the concentration of NT-proBNP was noted compared to the control groups. At the same time, the average NT-proBNP level in the study groups did not exceed the reference values. Significant correlations were revealed between NT-proBNP and heart rate (r 1 =0,462, p=0,010; r 3 =0,397, p=0,034), UCTD diagnostic cut-off level (r 1 =0,496, p=0,001; r 3 =0,401, p=0,043), the presence of mitral valve prolapse (r 1 =0,469, p=0,002) and mitral regurgitation (r 1 =0,53, p=0,008), premature ventricular contractions (PVCs) of class III (r 1 =0,582, p=0,045), IVa (r 1 = 0,39, p=0,042) and V (r 1 =0,397, p=0,037); cardiac index (r 1 =-0,329, p=0,037) and ejection fraction (r 1 =-0,407, p=0,044). However, no significant correlation was found between the left ventricular global longitudinal strain and NT-proBNP level. Conclusion. The study demonstrated the association of NT-proBNP level with UCTD diagnostic cut-off level, mitral valve prolapse, mitral regurgitation, and PVCs, which makes possible the use of this biomarker as an additional diagnostic criterion for myocardial changes in against the background of UCTD.