Abstract
BACKGROUND: The relationship between stress hyperglycemia and left atrial (LA) abnormality and left atrioventricular coupling in patients with acute myocardial infarction (AMI) has not been fully explored. This study aimed to assess the additive effect of hyperglycemia on LA phasic function and to investigate the atrioventricular interaction in patients with AMI via cardiac magnetic resonance imaging (MRI). METHODS: This study comprised 120 patients with AMI with admission normoglycemia (aNGL), 88 patients with AMI and admission hyperglycemia (aHGL), and 70 age- and sex-matched controls. LA volume (LAV), LA ejection fraction (LAEF), and LA reservoir/conduit/contraction strain (εs/εe/εa) were measured and compared. Subgroup analysis was performed according to the presence of LA enlargement [LAE; defined as a maximum LAV index (LAVImax) >55 mL/m(2)]. Univariate and multivariate linear regression analyses were employed to identify the independent factors related to LA phasic strains. RESULTS: Compared with controls, patients with AMI had increased LAVI and decreased LAEF and LA strains (all P values <0.05), and the LA reservoir [LA total ejection fraction (LATEF) and εs] and conduit [LA passive ejection fraction (LAPEF) and εe] dysfunction was also present in those without LAE (all P values <0.05). Furthermore, εs and εe were significantly reduced in the aHGL group as compared with the aNGL group (both P values <0.001). After adjustments were made for confounding clinical factors, admission blood glucose level (aBGL) was independently and significantly associated with εs (β=-0.211; P=0.002) and εe (β=-0.215; P=0.001) in patients with AMI. After the introduction of left ventricular (LV) indicators into multivariable regression models, LV global longitudinal strain (GLS) was significantly associated with εs (β=-0.467; P<0.001) and εe (β=-0.455; P<0.001). CONCLUSIONS: Hyperglycemia was found to exacerbate LA reservoir and conduit dysfunction in patients with AMI. aBGL and LV GLS were independent determinants of the εs and the εe, suggesting that attention should be paid not only to glucose monitoring but also to cardiac function indicators.