One-hour post-load glucose and subclinical left atrial myocardial dysfunction in hypertensive patients

Background: Recently, studies demonstrated that normal glucose-tolerant subjects (NGT) with one-hour post load plasma glucose value >155 mg/dl during oral glucose tolerance test (OGTT) (NGT≥155) present an impaired cardio-metabolic profile, with subclinical myocardial damage. Atrial morphological and functional alterations, closely related to diastolic dysfunction, are important predictors of atrial fibrillation (AF), cardiovascular (CV) events, and mortality in the entire population as well as in diabetic patients. The aim of our study was to evaluate subclinical atrial myocardial damage, assessed with speckle tracking echocardiography, in NGT≥155 mg/dl patients, comparing to NGT<155 mg/dl subjects, impaired glucose tolerant (IGT) individuals and patients with newly diagnosed type 2 diabetes (T2DM). Methods: We enrolled 229 Caucasian patients. All subjects underwent anthropometrical and hemodynamic parameters evaluation, OGTT, advanced Color-Doppler echocardiography with evaluation of main atrial and ventricular parameters. Results: As expected, from first to the fourth group there was a worsening of the metabolic profile as attested by fasting, one-hour and two-hour post load plasma glucose levels, during OGTT. Moreover, from NGT<155 to T2DM group there was an impairment in reservoir and pump atrial function (PALS and PACS, respectively) (p<0.0001). Conclusion: Present data demonstrated for the first time that NGT≥155 subjects present subclinical atrial dysfunction. These results may be clinically relevant because they highlight how atrial myopathy occurs early in pre-diabetes stage regardless of fibrotic and morphological alterations of the ventricular myocardium.