Significance: Heart failure (HF) has a high morbidity and mortality and its incidence is increasing worldwide. While protein biomarkers have been established for diagnostic and prognostic evaluation of patients with HF, there is currently no systematic assessment of RNA biomarkers. We determined the composition of myocardial tissue and circulating microRNAs (miRNAs) in a large cohort of patients with stable and advanced HF and compared it to the composition of normal adult and fetal samples. The advanced HF patients underwent mechanical unloading with left ventricular assist devices and samples were collected at different postoperative time points. Our findings provide the underpinning for miRNA-based therapies and emphasize the usefulness of circulating miRNAs as biomarkers for heart injury performing similar to established diagnostic protein biomarkers.

Introduction: The validated long Research Participant Perception Survey (RPPS-Long) elicits valuable data at modest response rates.Methods: To address this limitation, we developed shorter RPPS-Ultrashort and RPPS-Short versions, fielded them with the RPPS-Long to a random sample of a national research volunteer registry, and assessed response and completion rates, test/retest reliability, and demographics.Results: In total, 2228 eligible registry members received survey links. Response rates were 64% (RPPS-Ultrashort), 63% (RPPS-Short), and 51% (RPPS-Long), respectively (p<0.001). Completion rates were 63%, 54%, and 37%, respectively (p<0.001). All surveys were reliable with Cronbach α=0.81, 0.84, and 0.87, respectively. Retest reliability was highest for RPPS-short (κ=0.85). Provision of compensation increased RPPS-short completion rate from 54% to 71% (p<0.001). Compensated respondents were younger (p<0.001), with greater minority representation (p=0.03).Conclusions: Shorter surveys were reliable and produced higher response and completion rates then long surveys. Compensation further increased completion rates and shifted sample age and race profiles.