AKT1 and atrial fibrillation: Our findings reveal that atrial myocyte-derived miR-210-3p targets the GPD1L/PI3K/AKT pathway and functions as a crucial paracrine signaling mediator during atrial fibroblast cell proliferation; we also illustrate a novel role for miR-210-3p as a potential marker for the clinical diagnosis and identification of novel therapeutic targets in AF.