Independent effect of visceral fat on left atrial phasic function in the general population

Abstract

Background and aims: Obesity increases the risk for atrial fibrillation (AF), although the impact of abdominal fat distribution on left atrial (LA) morphology and functional remodeling remains unclear. This study aimed to investigate whether increased abdominal adiposity is independently associated with impaired LA function and/or LA enlargement in a sample of the general population and to evaluate the role of adipokines in this association.

Methods and results: The study cohort consisted of 527 participants (362 men; 57 ± 10 years) without overt cardiac disease who underwent laboratory testing, abdominal computed tomographic examination and echocardiography. Abdominal adiposity was quantitatively assessed as visceral fat area (VFA) and subcutaneous fat area (SFA) at the level of the umbilicus. Speckle-tracking echocardiography was performed to assess LA phasic function including reservoir, conduit and pump strain. LA reservoir and conduit strain decreased with increasing VFA quartiles (both p < 0.05), whereas no significant differences were observed in LA volume index and pump strain. When stratified by SFA, there were no significant differences in LA size and function across the quartiles. In multivariable analysis, VFA was significantly associated with LA conduit strain independent of cardiovascular risk factors, and pertinent laboratory and echocardiographic parameters (standardized β = -0.136, p = 0.019). VFA was correlated with serum adiponectin level (r = -0.51, p < 0.001), but there was no association between adiponectin level and three LA phasic strains.

Conclusion: In a sample of the general population, VFA accumulation was independently associated with worse LA conduit strain, which may be involved in the pathophysiological mechanism of obesity-related AF.

Keywords: Left atrial strain; Speckle-tracking echocardiography; Subcutaneous fat; Visceral fat.