Aim: An increased burden of cardiovascular disease is observed in prediabetes compared to normoglycemic. In this study, we aimed to evaluate left atrium (LA) volume indices and mechanical functions in prediabetes patients by real-time three-dimensional echocardiography (3DE) and examine the relationship of these parameters with N-terminal pro-atrial natriuretic peptide (NT-pro-ANP) levels.

Methods: 41 patients diagnosed with prediabetes by the oral glucose tolerance test in the endocrinology outpatient clinic and 43 healthy controls were included in this study. We evaluated the volume indices and mechanical functions of the LA using 3DE. Plasma NT-proANP was evaluated by the enzyme-linked immunosorbent assay method.

Results: Median NT-pro-ANP level was higher in the prediabetes group than the control group (1.5 vs 0.7 nmol/L, p<0.001). Levels of LA volume index (LAVI), minimum and maximum of LA volume (Vmin, Vmax; respectively), pre- atrial contraction volume (VpreA), active emptying fraction, and total and active emptying volume, each reflects reservoir and pump functions of LA, were higher in the prediabetes group. In contrast, the LA passive emptying fraction (PEF) level was lower (p<0.05). There was a positive correlation between levels of NT-pro-ANP and Vmax (r= 0.352, p=0.024), Vmin (r= 0.563, p<0.001), VpreA (r= 0.504, p<0.001), and LAVI (r= 0.338, p=0.031), while negative correlation existed between levels of NT-pro-ANP and total emptying fraction (r = -0.522, p<0.001) and PEF (r= -0.349, p=0.025) was found.

Conclusion: LA volume and mechanical functions are impaired in prediabetes patients, and this deterioration was positively correlated with NT pro-ANP levels. The current findings demonstrate that cardiac structural deterioration in prediabetes patients is just initiated before overt diabetes onset.

Keywords: glycemia, left atrium, N-terminal pro-atrial atriuretic peptide, prediabetes, three-dimensional echocardiography