Given the undeniable clinical and prognostic value, the function of the left atrium (LA) plays a leading role in the contemporary evaluation of cardiac diseases and is considered an essential morphological substrate for the development of cardiovascular diseases. It is sensitive to nervous, endocrine, and immunological stimuli. New evidence from the literature highlights the importance of fibrotic, electrical, and autonomic remodeling of the LA, introducing the concept of atrial cardiomyopathy, which is closely associated with atrial fibrillation and stroke. In the past, the diameter of the LA was the most important parameter for assessing its characteristics, but new information about the various roles of the LA has created the need for parameters that more precisely or thoroughly evaluate LA function. The function of the LA is complex, consisting of three phases: the reservoir phase (ventricular systole), the conduit phase (early diastole), and the pump phase (late diastole). The introduction of myocardial deformation analysis, or strain of the LA via speckle tracking, has achieved significant progress in detecting even subtle functional abnormalities before an increase in LA size. This method improves the diagnostic capabilities of standard echocardiographic examinations, and its diagnostic and prognostic value is sometimes comparable to more advanced and less accessible techniques such as cardiac magnetic resonance imaging and computed tomography.

BACKGROUND Left atrial (LA) strain analysis has emerged as a noninvasive technique for assessing LA function and early detection of myocardial deformation. Recently, its application has also shown promise in the pediatric population, spanning diverse cardiac conditions that demand accurate and sensitive diagnostic measures. OBJECTIVE This research endeavors to explore the role of LA strain parameters and contribute to the growing body of knowledge in pediatric cardiology, paving the way for more effective and tailored approaches to patient care. METHODS A comprehensive literature review was conducted to gather evidence from studies using echocardiographic strain imaging techniques across pediatric populations. RESULTS LA strain parameters exhibited greater sensitivity than conventional atrial function indicators, with early detection of diastolic dysfunction and LA remodeling in pediatric cardiomyopathy, children with multisystem inflammatory syndrome, rheumatic heart disease, as well as childhood renal insufficiency and obesity offering prognostic relevance as potential markers in these pediatric subpopulations. However, there remains a paucity of evidence concerning pediatric mitral valve pathology, justifying further exploration. CONCLUSION LA strain analysis carries crucial clinical and prognostic implications in pediatric cardiac conditions, with reliable accuracy and sensitivity to early functional changes.

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The fibrosis of the LA, which is characteristic of AF, causes mechanical dysfunction of the LA and may also be present in patients without LA enlargement. LA strain represents a surrogate marker of this mechanical dysfunction. Early detection of LA dysfunction may be crucial in identifying patients who are more likely to experience AF recurrence following cardioversion and ablation. Before cardioversion and ablation, the probability of AF recurrence might be predicted, which could lead to better patient selection, an individualized therapeutic strategy with reduced risk and focused follow-up. Purpose The aim of this study was to evaluate the additional predictive value of LA function assessed by using strain echocardiography for early AF recurrence after cardioversion and ablation. Methods 94 patients diagnosed with symptomatic persistent atrial fibrillation (EHRA symptom score ≥3 (mean age 59.4 ± 12.2 years, 58% male, 42%female), preserved LV ejection fraction were prospectively analyzed. In 39 (41,5%) patients pharmacological cardioversion was done after saturation with antiarhythmic drugs,in 27 (28,7%) patients planed electrical cardioversion was done after medical saturation with antiarrhythmic drugs and failure of pharmacological cardioversion, and in 28 (29,8%) patients planed RF ablation was performed. Complete echocardiography evaluation including strain and volume index LA was performed before cardioversion and ablation. The rhythm evaluation was done in the first month after cardioversion and RF ablation (35±5 days). The primary endpoint was persistent AF recurrence. Results 29 (30,8%) patients had AF recurrence in the overall study population, independently of duration of AF or method of rhythm control. Peak atrial longitudinal strain (PALS) ≤15% had the highest incremental predictive value for AF recurrence (HR =8.42, 95% CI: 3.17–25.12, p < 0.001). In patients with non-dilated LA, PALS≤15% remained an independent predictor of AF recurrence (HR = 5.32, 95% CI: 1.77–17.42, p = 0.005). Conclusion This study shown that, in addition to LA dilatation, LA function as determined by PALS can provide a prognostic value for early AF recurrence after cardioversion or ablation. PALS also predicted AF recurrence in patients with nondilated LA. These findings highlight the additional prognostic usefulness of LA strain and recommend its implementation in the systematic assessment of AF patients prior to the choice of rhythm/rate control.