Correlation of NT-proBNP and left atrial pressure in patients with atypical atrial flutter after cardiac surgery and previous catheter ablation

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Atypical atrial flutter (AFL) is often associated with cardiac surgery or extensive catheter ablation (CA) for the treatment of atrial fibrillation (AF). Therefore, the increase in the number of cardiac surgery procedures leads to the development of substrates for atypical AFL onset. Described several prognostic factors for the development of AF in the long-term period after cardiac interventions. To our knowledge, the prognostic factors of atypical AFL in patients after cardiac surgery are not described. OBJECTIVE: the aim of our study was to determine the relationship between increased left atrial pressure and the NT-proBNP biomarker in patients after cardiac surgery and catheter ablation. METHODS: Sixty-five adult patients with AFL after cardiac surgery and catheter ablation were included in a single-center prospective study. The patients' age varied from 18 to 76 years, and the mean age was 57.1±12.2 years. Of these, 36 patients were male (55.4%) and 29 women (49.3%), respectively. Patients were observed for NT-proBNP before index radiofrequency ablation (RFA). All patients underwent RFA of atypical AFL in the left atrium (LA) and measurement of LA pressure. The patients were discharged safely and were monitored for 12 months. RESULTS: According to basic characteristics of patients with atypical AFL cardiac surgery for valvular heart disease was performed in 30 (46.1%) cases, for ischemic and congenital heart diseases occurred with the same frequency, 8 (12.3%). Atypical AFL occurred in 20 (30.8%) cases after cryoballoon pulmonary veins isolation (PVI), after RFA of a typical AFL in 14 (21.3%) cases, and radiofrequency PVI in 13 (20%) cases. The mean invasive LA pressure before index RFA was 22.3±5 mm. Hg, mean LA size on transthoracic echocardiography was 42.3±6.9mm. The parameters of the left ventricle: mean EDV 93.3±26.1ml, mean ESV 41.7±16.9ml, and mean EF 56±7.6%. Mean NT-proBNP was 974.8±440.5 pg/ml. In our cohort of patients, we identified a positive correlation between NT-proBNP and LA pressure (p<0.001, r=0.761), as well as a positive relationship between NT-proBNP and LA diameter (r=0.512, p<0.001), between LA pressure and LA diameter (r=0.438, p<0.001). Additionally, a correlation was found between the pulmonary artery systolic pressure and LA diameter (r=0.314, p=0.011). CONCLUSIONS: Our study demonstrates a strong direct linear relationship of NT-proBNP with an increase of LA pressure in patients with atypical AFL in patients previously undergone cardiac surgery and catheter ablation. Thus, these parameters can serve as possible prognostic criteria for the development of complex cardiac arrhythmias such as atypical AFL.