Degenerative mitral valve disease is the most common cardiac disease in dogs, primarily affecting small breeds, and progresses from a heart murmur to congestive heart failure causing breathlessness and suffering.
Dogs with congestive heart failure from DMVD experience breathlessness - the distressing sensation of air hunger that comes from fluid accumulating in the lungs. The coughing episodes are exhausting and distressing. Even before overt heart failure, dogs with significant regurgitation may have reduced exercise tolerance, becoming breathless and fatigued more easily. The anxiety of recurrent breathlessness and the loss of previously enjoyable activities like walks significantly affects quality of life. The EPIC trial finding that pimobendan delays heart failure onset when started before clinical signs provides a meaningful welfare intervention - extending months of comfortable life for high-risk dogs through proactive treatment.