The left atrium (LA) is integral in maintaining hemodynamic function, serving as a reservoir, conduit and pump for left ventricular (LV) filling, and regulator of volume through natriuretic peptide secretion. Consequently, LA dysfunction is associated with adverse clinical implications, highlighting the importance of its identification. This is particularly true in the setting of atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF), as both syndromes are highlighted by LA dysfunction. Herein, we argue for the systematic identification of LA myopathy to guide tailored therapy in AF and HFpEF.