Importance of left atrial strain in the assessment of cardiac function

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.