ABSTRACT Cardiovascular disease (CVD) remains a leading cause of death worldwide. Dilated cardiomyopathy (DCM), a major cause of heart failure (HF), exhibits ventricular dilation, impaired systolic/diastolic function, arrythmias, and adverse cardiac remodeling. While genetic causes of DCM have been extensively studied, non-genetic and acquired forms of DCM-like HF are less well characterized, especially with respect to non-coding RNA regulation. Circular RNAs (circRNAs) are stable, covalently closed non-coding RNAs that regulate cellular function via sequestering miRNAs, RNA-binding proteins, or translation. Their role in canine HF that recapitulates features of non-genetic DCM remains largely unexplored. To address this, we developed K9HeartCircDB ( https://www.k9heartcircdb.com/ ), a publicly accessible database that catalogs circRNAs expressed in canine left ventricular (LV) tissues under tachypacing-induced HF, a model of non-genetic DCM-like disease, and healthy control conditions. The online interface enables users to query and explore circRNAs based on exon composition, predicted miRNA binding sites, protein-coding potential, siRNA targets, and primer design for experimental validation. By providing an integrated and user-friendly platform for canine heart circRNA exploration, K9HeartCircDB offers a valuable resource to facilitate mechanistic and advance translational studies on non-genetic DCM-like disease.