BACKGROUND/AIM Early detection of left ventricle (LV) systolic dysfunction could be a clue for surgical treatment in patients with significant aortic stenosis (AS). Therefore, we evaluated LV peak of global longitudinal strain (PGLS) using speckle tracking imaging at rest and during low-dose dobutamine infusion in asymptomatic patients with moderate and severe AS and preserved LV ejection fraction (EF). METHODS All the patients underwent coronary angiography and had no obstructive coronary disease (defined as having no stenosis greater than 50% in diameter). The patients were divided into two groups: above and below median of 0.785 cm2 aortic valve area (AVA). PGLS was measured from acquired apical 4-chamber and 2-chamber cine loops using a EchoPac PC-workstation at rest and during 5 microg/kg/min, 10 microg/kg/min, and 20 microg/kg/min dobutamine infusion, respectively. The global strain was the average of segment strains from the apical views. RESULTS A total of 62 patients with moderate and severe AS (AVA < = 1.5 cm2), the mean age 66.12 +/- 9.91, (57.14% males), were enrolled in this prospective study. At rest, mean gradient was 43.57 +/- 0.29 mmHg and mean EF was 72.24 +/- 0.45%. When divided according to median AVA, both groups had decreased average PGLS at rest (-9.33 +/- 4.46% vs -8.95 +/- 3.08%; p = ns). During dobutamine both groups increased their average PGLS, but only the group with AVA > median reached the statistical significance (- 8.71 +/- 2.68% vs -11.93 +/- 3.74%, p = 0.002). In addition, PGLS increase was also significant in 4-chamber view in the patients with AVA above median, but only when comparing baseline to peak 20 microg/kg/min (-10.72 +/- 3.07% vs -13.14 +/- 4.79%; p = 0.034). Conversely, in both groups the increase of PGLS in 2-chamber view did not reach significance. CONCLUSION Two-dimensional strain speckle tracking analysis of myocardial deformation with measurement of peak systolic strain during dobutamine infusion is a feasible and accurate method to determine myocardial longitudinal systolic function and contractile reserve and may contribute to clinical decision making in patients with significant AS.

BACKGROUND/AIM Impaired endothelial function has been previously documented in patients with atrial fibrillation (AF) and underlying comorbidities or older patients with idiopathic AF. The aim of this study was to evaluate systemic endothelial function in younger AF patients (less than < 60 years old) with lone AF (that is, without associated cardiopulmonary comorbidities, including arterial hypertension), by comparing brachial artery flow-mediated dilation (FMD) in lone AF patients with FMD of healthy subjects in sinus rhythm. METHODS Two groups of participants were prospectively enrolled. The first group comprised of 38 AF patients (the mean age 45 +/- 11 years, 68% male) with persistent (> 7 days) lone AF. The second group comprised of 28 healthy controls in sinus rhythm (the mean age 43 +/- 13, 53% male), matched by age, gender and atherosclerotic risk factors. All the participants underwent physical examination, laboratory analysis [including determination of C-reactive protein (CRP)], standard echocardiography and exercise-stress testing. Brachial artery FMD and endothelium independent dilation (NMD) were assessed with a high-resolution ultrasound probe and arterial diameters taken from 5 consecutive cardiac cycles were averaged for each measurement to accommodate to beat-to-beat flow variations in AF. RESULTS There were no differences between the 2 groups regarding age, gender and most clinical, laboratory and echocardiographic characteristics (all p > 0.05), apart from the increased heart rate (p = 0.018), body mass index (p = 0.027), CRP levels (p = 0.007) and left atrial anteroposterior dimension (p < 0.001) in AF patients. FMD of AF patients [median value 5.0%, interquartile range (IQR) 2.87%-7.50%] was significantly lower (p < 0.001) than FMD of healthy controls (median value 8.85%, IQR 5.80%-12.50%), whereas there were no differences in median NMD values (p > 0.05). In the multivariate analysis, the independent FMD determinants in our study population were the presence of AF, smoking and total cholesterol levels (all p < 0.001). In patients with AF, the strongest independent FMD determinant was arrhythmia duration (p < 0.001), followed by smoking (p = 0.013) and total cholesterol levels (p = 0.045). CONCLUSIONS Our findings confirm that sustained AF is associated with systemic endothelial dysfunction even in relatively young patients with no cardiovascular disorders or risk factors. AF is an independent contributor to lower FMD and a prolonged arrhythmia duration may confer the risk for more profound endothelial damage.