ABSTRACT This application proposing the CHIcago Center for Accelerating nextGen Omics, deep phenotyping, and data science in Heart Failure (CHICAGO-HF) is in response to the RFA “HeartShare: Next-Generation Phenomics to Define Heart Failure Subtypes and Treatment Targets-Clinical Centers.” Heart failure with preserved ejection fraction (HFpEF) is associated with significant morbidity and mortality and is increasing in prevalence. No effective disease-modifying therapies exist for patients with HFpEF, largely due to the substantial heterogeneity among patients with HFpEF for whom the current “one-size-fits-all” treatment paradigm is failing. A large-scale, multicenter observational study to conduct deep phenotyping in patients with HFpEF is a critical next step to advance our understanding of HFpEF pathophysiology and shift our clinical and research paradigm in HFpEF towards a precision medicine approach. We propose three central elements that are critical to address to comprehensively phenotype patients across the spectrum of HFpEF. First, direct phenotyping of the myocardium, using tools such as magnetic resonance imaging (MRI) and endomyocardial biopsy, is necessary to elucidate the intrinsic myocardial biology of HFpEF. Second, detailed phenotyping of the complex interplay of extra-cardiac comorbidities is needed to better understand the systemic nature of HFpEF. Third, a representative sample of HFpEF patients with diversity across sex, race/ethnicity, geography, and socioeconomic status needs to be included in phenotyping efforts to prevent widening of well-documented disparities in HFpEF. The proposed Clinical Center, CHICAGO-HF, led by Northwestern, is uniquely qualified to participate in all aspects of the HeartShare Network and to substantially enhance the Network’s goals. In our application, we demonstrate key prior experiences, which include: (1) development of the world’s first dedicated clinical program in HFpEF; (2) recruitment of large numbers of patients with HFpEF into multicenter observational studies and trials; and (3) participation as a Field Center for NHLBI-funded cohorts. Our well- resourced multi-disciplinary investigative team has expertise in epidemiology, informatics, deep phenotyping, and artificial intelligence. We will leverage our experiences with our robust electronic health record infrastructure to efficiently collect, harmonize and share retrospective and prospective data on a large number of diverse patients with HFpEF and age- and sex-matched controls (HF with reduced and mid-range EF and healthy controls). We will prospectively recruit at least 250 patients within the study timeline with community partners across Chicago (e.g. Federally Qualified Health Centers). In addition, our unique expertise in innovative MRI techniques and data analytics can strengthen the Network and will enable testing of significant and innovative hypotheses to define unique phenotypes, elucidate distinct endotypes that represent un...