ABSTRACT Roughly 20,000 patients per year are treated with ablation to treat atrial fibrillation (AF) because their condition cannot be managed by pharmaceuticals alone. While ablation protocols exist that can treat the disease in many cases, these procedures can be lengthy (2-4 hours) and are only somewhat effective (~60-70% success). This speed of the procedure is limited by electrophysiology tools, which still require serial mapping of the atrium based on articulating an electrode (or electrode array) around the patient anatomy. Furthermore, because AF is an unstable arrhythmia, it is difficult to construct full spatiotemporally resolved electrocardiograms from this type of serial mapping. The small subset of devices that provide simultaneous mapping of the entire chamber have serious limitations and often leave large portions of the chamber unmapped. Here, we propose the use of a flexible and conformal soft robotic sensor array that allows for rapid, efficient and high resolution mapping of the left atrium for treatment of AF. Our lab has already established prototype devices based in vitro assessments in patient specific 3D print models. In this proposal, we will develop an optimized prototype, and associated catheter, based on a series of in vivo surgical and finally, percutaneous large animal studies. Once optimized, during the R33 phase, we will perform a series of device validation protocols based on ISO and ASTM standards. Finally, during the R33 phase of the proposal we will validate the system in vivo using large animal models.