Electromechanical Uncoupling in Critical Illness: Arrhythmia Mechanisms During ECMO and Ventricular Assist Device Support

Electromechanical uncoupling is increasingly recognized as a key mechanism underlying arrhythmias in patients supported with extracorporeal membrane oxygenation (ECMO) and ventricular assist devices. This review summarizes current evidence on how mechanical unloading, altered preload and afterload conditions, myocardial stretch, inflammation, hypothermia, and electrolyte disturbances contribute to electrical instability during mechanical circulatory support. We describe device-specific arrhythmia patterns, including atrial fibrillation in venovenous ECMO, ventricular tachyarrhythmias and electrical storm in venoarterial ECMO, and suction- or remodeling-related arrhythmias in continuous-flow left ventricular assist devices. We also review findings from electrophysiologic mapping, strain imaging, and cardiac magnetic resonance imaging that characterize the evolving arrhythmic substrate during support. Emerging technologies such as artificial intelligence prediction models, computational mechanoelectric simulations, and sensor-based device analytics offer promising tools for early detection and individualized management. Despite these advances, current data remain limited by small sample sizes, heterogeneous populations, and a lack of standardized definitions or prospective validation. A deeper understanding of dynamic electromechanical interactions, combined with integrated monitoring and refined device management strategies, will be essential to improve rhythm stability, myocardial recovery, and overall survival.