Abstract
Background Atrial fibrillation (AF) and atrial cardiomyopathy (AtCM) share overlapping pathophysiological processes, with abnormalities in atrial structure and function being key contributors to disease progression. Aim This study aimed to assess echocardiographic parameters and circulating biomarkers in middle-aged AF patients without previously known overt heart disease, to explore early markers of atrial dysfunction and AtCM. Methods Prospective, consecutive patients (n = 970) who had been admitted for symptomatic AF to our hospital from January 2016 to January 2018 were screened for participation in the study. A total of 70 patients met the inclusion criteria: stable sinus rhythm, age between 40 and 60 years, and structurally normal hearts assessed by conventional two-dimensional echocardiography (2DE). They were separated into two groups: new-onset AF (n = 33) and recurrent episodes of paroxysmal AF (n = 37). Thirty age-matched healthy subjects were enrolled in the control group. All patients underwent 2DE assessment with volumetric and speckle-tracking analyses. Galectin-3, high-sensitivity troponin I (hsTnI), and high-sensitivity C-reactive protein (hsCRP) were measured. Results Significant structural and functional impairments were observed in both atria among AF patients, with the left atrium (LA) showing more pronounced abnormalities. Key parameters, such as LA reservoir and contractile strain, as well as electromechanical delay (EMD), were notably reduced. Individuals with paroxysmal AF exhibited elevated galectin-3 and hsTnI concentrations compared to both new-onset AF patients and controls, indicating more advanced fibrosis and myocardial stress. Furthermore, LA stiffness index and strain measures correlated strongly with galectin-3 levels. Conclusion In middle-aged patients without overt heart disease, advanced echocardiographic parameters (particularly strain and EMD), combined with biomarkers such as galectin-3 and hsTnI, represent sensitive markers for early atrial dysfunction and AtCM. The integration of these diagnostic tools may improve early detection, facilitate risk assessment, and support timely therapeutic interventions to prevent the progression of AF.