Speckle-Tracking Echocardiography of the Left Atrium as a Primary Tool for Detecting Functional Changes in Atrial Fibrillation

Introduction. Atrial fibrillation (AF) is the most common cardiac rhythm disorder and is associated with structural and functional remodeling of the left atrium (LA). Traditional echocardiographic parameters, particularly indexed LA volume, primarily reflect late stages of remodeling. Speckle-tracking-echocardiography (STE) enables the assessment of LA functional status at earlier stages through the analysis of myocardial deformation. Aim. To evaluate the functional status of the left atrium in patients with atrial fibrillation using speckle-tracking echocardiography by analyzing the indicators of LA deformation and comparing them with a healthy control group. Materials and Methods. Eighty patients were included in the study and divided into two groups: a control group (n=40) without atrial fibrillation and a research group (n=40) with documented paroxysmal or persistent AF, all of whom had normal sinus rhythm at the time of examination. All participants underwent transthoracic echocardiography to determine indexed LA volume (LAVI), LA ejection fraction, LA diameter, and left ventricular functional parameters. Speckle-tracking echocardiography was performed to calculate reservoir (LASr), conduit (LAScd), and contractile (LASct) strains of the LA. Statistical analysis included comparison of mean values between groups and logistic regression with calculation of odds ratios (OR). Results. Patients with atrial fibrillation had significantly larger LA dimensions and volumes compared to the control group (LAVI: 39.7±14.1 ml/m² vs. 28.2±5.8 ml/m²; p<0.001). Measures of LA reservoir and conduit functions were markedly lower in the AF group: LASr was 23.5±9.1 % vs. 38.3±9.2 % in controls (p<0.001), and LAScd was -13.9±5.1 % vs. -25.5±7.3 % (p<0.001). LA contractile function (LASct) was also lower in AF patients, although this difference did not reach statistical significance. Logistic regression analysis showed that each 1 ml/m² increase in LAVI was associated with a 10 % higher likelihood of AF (OR=1.10; 95 % CI 1.04-1.16; p<0.001), while each 1 % decrease in LASr corresponded to a 28 % higher likelihood of AF (OR=1.28; 95 % CI 1.16-1.42; p<0.001). Conclusions. Patients with atrial fibrillation exhibit significantly impaired left atrial function compared to controls, even in the presence of normal sinus rhythm. LA strain, particularly reservoir strain (LASr), is a more sensitive marker of atrial cardiomyopathy than structural parameters alone. Speckle-tracking echocardiography is an effective tool for the early detection of functional changes in the left atrium in patients with atrial fibrillation.