The role of biomarkers, sleep apnea and echocardiography as predictors of atrial fibrillation in a pacemaker population

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Sleep apnea, dilated left atrial has been related to a higher possibility to develop atrial fibrillation (AF). Some pacemakers are able to detect periods of apnea during the sleeping time obtaining a respiratory disturbance index (RDI) related to sleep apnea (SA), as well as atrial high rate episodes (AHREs) that are also predictors of AF. Another possible predictor of AF is galectin-3, a biomarker related to fibrotic phenomena. This study aims to evaluate the relationship between ARI and AHRE detection, as well as the relationship between left atrial size measured by echocardiography and some biomarkers with the development of AHREs. METHODS: This is a single-centre, prospective, non-randomized, descriptive study carried out in a tertiary hospital, including patients with dual-chamber pacemaker able to detect SA, initially in sinus rhythm. Patients were included at the implantation date, between November 2015 and November 2018, and medium follow-up was 2 years. Those with a previous diagnosis of AF were not included. In a baseline visit, clinical, anthropometric characteristics, as well as echocardiography and analytical parameters were obtained, including NTproBNP, galectin-3 and ST-2. In addition to the baseline visit, device interrogation visits at six months, one year and tho years in order to obtain atrial activity and SA registers were performed. Those whose apnea recordings were illegible were excluded from the analysis. We performed a descriptive statistical analysis with Microsoft Excel. RESULTS: 102 patients with dual chamber pacemaker were included. 79 of the pacemakers provided legible apnea and atrial activity recordings. 22 of them showed an RDI>20 in more than 75% of the nights, and 38 of them recorded AHRE longer than 6 minutes in 24 hours. Tables 1 and 2 show baseline characteristics and the AHRE (episodes with duration >6 minutes) and RDI recordings suggestive of severe SA (RDI>20 in more than 75% of the nights). Differences in AHRE between both RDI groups did not reach statistical significance. After univariate analysis, the multivariate analysis showed significant relationship between AHRE >6 minutes and the galectin-3 level at baseline as well as between AHRE>6 minutes and the left atrial indexed volume at baseline. CONCLUSION: In our study, 48% of the pacemakers registered AHRE longer than 6 minutes in 24 hours. No statistical relationship between RDI and AHRE was found. Baseline galectin-3 level and left atrial indexed volume appeared to be related to the development of AHRE in the follow-up. [Figure: see text] [Figure: see text]