P814 Independent association of body mass index and left atrial strain in patients with non valvular atrial fibrillation. The NeAfib-Echo registry
Authors: Esposito L , Sorrentino R , Capone V , Santoro C , Lembo M , Esposito R , Lo Iudice F , De Roberto A M , Tufano A , Galderisi M 
Published: January 2020

Abstract

Background
Overweight and obesity are related to the risk of new-onset atrial fibrillation (AF). Peak atrial longitudinal strain (PALS) is an advanced echocardiographic parameter of left atrial (LA) function with a recognized diagnostic and prognostic role in both the general population and AF.

Purpose
To investigate the impact of body mass index (BMI) on LA function by utilizing standard and advanced echocardiography in patients with non-valvular AF.

Methods
In the NeAfib-Echo registry, 395 consecutive adult patients with non-valvular AF (F/M: 175/220; mean age 70.6 ± 11 years, BMI: 27.8 ± 5.6 kg/m²) were enrolled. 215 patients (54.1%) had permanent/persistent AF (prAF) and 178 (45.9%) had paroxysmal AF (pxAF). Anthropometric parameters and blood pressure (BP) were recorded and CHA2DS2VASc score was calculated. Patients underwent a complete echo-Doppler exam, including determination of PALS and left ventricular (LV) global longitudinal strain (GLS) (both reported in absolute values). The overall population was divided according to BMI tertiles: first tertile &lt;25.3 Kg/m² (n = 127); second tertile 25.3-29 Kg/m² (n = 137); third tertile &gt; 29.3 Kg/m² (n = 130).

Results
No significant difference of sex prevalence, age, systolic BP and heart rate was found among the three BMI tertiles, whereas diastolic BP was higher in the third tertile (p &lt; 0.001). CHA2DS2VASc score did not significantly differ among tertiles. In the pooled population LV mass index (LVMi) (p = 0.001) progressively increased from the first to the third tertile (p &lt; 0.001), whereas LA volume index, LV ejection fraction (EF), GLS and E/e" ratio were not significantly different among the three groups. PALS was lower in third tertile (14.3 ± 8.2%) versus both the first (19.0 ± 11.5%) and the second tertile (17.7 ± 10.6%) (p &lt; 0.002). In separate sub-analyses according to AF type, PALS was significantly lower in the first than the third tertile in the PxAF group (p &lt; 0.01) but not in patients with PrAF (p = 0.158). In the pooled population PALS was significantly related with BMI (r= -0.17, p &lt; 0.001) (Figure) but also with age, heart rate, LVMi, LV EF, GLS, E/e’ ratio and pulmonary artery systolic pressure (PAPS). By a multilinear regression analysis, after adjusting for CHA2DS2VASc score, LV mass index, LV EF, E/e’ ratio and PAPs, BMI remained independently associated with PALS (standardized β coefficient = -0.127, p &lt; 0.02) (cumulative R² =0.41, SEE = 8.5%, p &lt; 0.0001).

Conclusions
In patients with non valvular AF, overweight and obesity exert a detrimental effect on LA function as testified by the gradual PALS reduction with the increase of BMI tertiles. BMI is associated with PALS independently of several confounders including CHA2DS2VASc. Besides CHA2DS2VASc score, BMI could be considered as an additional factor for evaluating cardiovascular risk in non valvular AF.
Abstract P814 Figure. Relation between BMI and PALS