2025 Cardiac Arrhythmia Mechanisms Gordon Research Conference and Gordon Research Seminar - PROJECT SUMMARY – Gordon Research Conference/Seminar on Cardiac Arrhythmia Mechanisms Disorders of heart rhythm are leading causes of sudden death and stroke. Progress in elucidating molecular, cellular, and systems-level mechanisms has promoted new concepts that have guided the development of more effective diagnostic and therapeutic strategies. However, cardiac arrhythmias remain major causes of morbidity and mortality throughout the world. Due to the emergent, multi-scale nature of cardiac arrhythmias, inter- disciplinary approaches are needed to solve the most urgent problems. From its inception in 2003, the GRC on Cardiac Arrhythmia Mechanisms has sought to integrate knowledge across multiple scales to better understand and treat cardiac rhythm disorders. The theme of the 2025 GRC on Cardiac Arrhythmia Mechanisms is: Recognizing diversity of cells, systems & individuals to advance arrhythmia therapy. This meeting will emphasize cellular, systems-level, and inter-individual diversity to provide novel, multi-scale insight into arrhythmia biology and pathogenic mechanisms. The meeting will also highlight emerging multidisciplinary investigational and therapeutic approaches for the diagnosis and treatment of cardiac arrhythmias. This biennial conference is widely regarded by the arrhythmia biology community as the premier forum in which cutting edge concepts and new observations on mechanisms and treatment of cardiac arrhythmias are discussed, through an integrated program that spans the molecular, cellular, tissue, and organ levels up to clinical translation. The first Aim of the meeting is to share the latest advances in mechanisms of cardiac arrhythmias from multi- disciplinary perspectives using state-of-the-art methodologies. Consistent with our theme of diversity within and between hearts, we developed sessions that will cover the roles of non-myocytes, precision medicine, and a variety of topics that impact diverse populations. The second Aim is to promote networking and spark new interdisciplinary collaborations. The meeting will bring together cell biologists, electrophysiologists, and clinician- scientists, as well as expert experimentalists and mathematical modelers all working on similar problems with diverse perspectives. The third Aim is to promote and increase representation of early-stage investigators, gender minorities, scientists from historically marginalized groups, and persons with disabilities in the cardio- vascular field. We are seeking partial support for registration and travel for trainees from these groups to attend both the GRS and GRC. Our goal is to promote the professional growth of a diverse and inclusive generation of cardiovascular scientists.