In the USA, 5.7 million Americans ≥20 years have heart failure (HF) and heart failure preserved ejection fraction (HFpEF) accounts for at least 50 % of all hospital admissions for HF. HFpEF has no single guideline for diagnosis or treatment, the patient population is heterogeneously and inconsistently described, and longitudinal studies are lacking. The primary aims of this manuscript were to present an integrated review of the current state of the science on HFpEF, demonstrate gaps in the literature and provide the rationale for the design and implementation of future research to yield insights into the syndrome of HFpEF. The scientific literature was comprehensively reviewed on HFpEF pathophysiology, patient characteristics, diagnostic criteria, echocardiography biomarkers, treatment approaches and outcomes. Discrepancies in patient characteristics, diagnostic criteria, study methods and echocardiographic biomarkers were identified. This review indicates that no single test or guideline exists for diagnosis or treatment for HFpEF; heterogeneity of the population is complicated by multiple comorbidities that factor into etiology, race and age are likely important factors that define the phenotype, and limited information is available that designates early markers of impending HFpEF. Studies designed and adequately powered to study the impact of race and age along with consistent use of HFpEF diagnostic criteria are critically needed to further incident HFpEF research.