The left atrium (LA) is pivotal in cardiac hemodynamics, serving as a dynamic indicator of left ventricular (LV) compliance and diastolic function. The LA undergoes structural and functional adaptations in response to hemodynamic stress, infiltrative processes, myocardial injury, and arrhythmic triggers. Remodeling of the LA in response to these stressors directly impacts pulmonary circulation, eventually leading to pulmonary capillary involvement, pulmonary artery hypertension, and eventually right ventricular failure. LA dysfunction and fibrosis also contribute to the future risk of atrial arrhythmias and mitral regurgitation. The parameters of LA size and function are being recognized as robust markers for the progression of several cardiac pathologies as well as important tools for prognostication. In this article, we briefly describe the different modalities and markers used to evaluate LA pathology in patients with nonischemic cardiomyopathies (NICM). We then provide an overview of the studies that compared the association of the different LA parameters with disease severity and future prognosis. We also identify the gaps in knowledge before these LA parameters make a case for clinical adoption.