BackgroundCirculating microRNAs are emerging biomarkers for heart failure (HF). Our study aimed to assess the prognostic value of microRNA signature that is differentially expressed in patients with acute HF.Methods and ResultsOur study comprised a screening cohort of 15 patients with AHF and 5 controls, a PCR‐discovery cohort of 50 patients with AHF and 26 controls and a validation cohort of 564 patients with AHF from registered study DRAGON‐HF (Diagnostic, Risk Stratification and Prognostic Value of Novel Biomarkers in Patients With Heart Failure). Through screening by RNA‐sequencing and verification by reverse‐transcription quantitative polymerase chain reaction, 9 differentially expressed microRNAs were verified (miR‐939‐5p, miR‐1908‐5p, miR‐7706, miR‐101‐3p, miR‐144‐3p, miR‐4732‐3p, miR‐3615, miR‐484 and miR‐19b‐3p). Among them, miR‐19b‐3p was identified as the microRNA signature with the highest fold‐change of 8.4 and the strongest prognostic potential (area under curve with 95% CI, 0.791, 0.654–0.927). To further validate its prognostic value, in the validation cohort, the baseline level of miR‐19b‐3p was measured. During a follow‐up period of 19.1 (17.7, 20.7) months, primary end point comprising of all‐cause mortality or readmission due to HF occurred in 48.9% patients, while patients in the highest quartile of miR‐19b‐3p level presented the worst survival (Log‐rank P<0.001). Multivariate Cox model showed that the level of miR‐19b‐3p could independently predict the occurrence of primary end point (adjusted hazard ratio,1.39; 95% CI, 1.18–1.64). In addition, miR‐19b‐3p positively correlated with soluble suppression of tumorigenicity 2 and echocardiographic indexes of left ventricular hypertrophy.ConclusionsCirculating miR‐19b‐3p could be a valuable prognostic biomarker for AHF. In addition, a high level of circulating miR‐19b‐3p might indicate ventricular hypertrophy in AHF subjects.RegistrationURL: https://www.clinicaltrials.gov. Unique Identifier: NCT03727828.