Dilated cardiomyopathy in juvenile large-breed rabbits (Oryctolagus cuniculus): 3 cases (2019-2025)

Background Dilated cardiomyopathy phenotype (DCMph) is rarely reported in juvenile pet rabbits ( Oryctolagus cuniculus ). Case description Three cases of DCMph in large-breed male rabbits <1 years of age (two intact, one castrated, weight range 3.3–3.8 kg at time of diagnosis) are described. All rabbits had non-specific or absent signs of disease on initial physical exam, but had elevations in alanine aminotransferase (ALT) above 130 U/L. Two of the cases were littermates that presented for routine castrations. The third case had a concurrent diagnosis of Eimeria (unspeciated). Diagnostic testing to investigate the ALT elevations was performed, and DCMph diagnoses were made via echocardiogram in each case. Medical management was initiated with a variety of treatments, including furosemide, enalapril, pimobendan, spironolactone, and nutraceutical supplements. One case was euthanized 283 days after DCMph diagnosis due to unrelated septicemia onset; the other two cases are alive at the time of publication (2444 days and 1743 days post diagnosis, respectively). Conclusions and clinical relevance This case series suggests a possible genetic etiology of DCMph in young, large breed rabbits, with a longer lifespan than previously reported in retrospective studies. Early diagnosis with long term-medical management may help improve outcomes.