Abstract
Background:
Myxomatous mitral valve disease (MMVD) is a common cause of congestive heart failure (CHF) in small-breed dogs. Clinical observations suggest that discontinuation of loop diuretics may be feasible in a subset of dogs with MMVD and CHF.

Aim:
To characterize dogs with MMVD-related CHF that achieved stability following loop diuretic withdrawal and to investigate potential contributing factors.

Methods:
We retrospectively analyzed 3,055 canine medical records of dogs diagnosed with MMVD (2012–2022) from the National Chung Hsing University Veterinary Medical Teaching Hospital database. Dogs considered stable and not requiring diuretic administration for at least 1 year after CHF diagnosis were included.

Results:
Six dogs (5 Maltese and 1 Toy Poodle) with a median age of 8.5 years and a median weight of 3.18 kg met the inclusion criteria. These dogs achieved stability after a median treatment duration of 675 days (range: 77–917 days) and were followed up for a period of 386–1572 days. The presence of azotemia, radiographic evidence of reduced heart size, and evidence of long-term clinical stability supported diuretic tapering. All cardiac medications were discontinued in three dogs, while the remaining three continued pimobendan-based therapy.

Conclusion:
CHF secondary to MMVD in dogs can stabilize in rare instances without lifelong diuretic administration. These observations suggest that reversible or transient factors may contribute to the initial presentation of CHF in selected cases. Regular cardiac and renal assessments may help in identifying suitable candidates for diuretic adjustment when concurrent systemic conditions, such as azotemia, pose a limiting side effect despite sustained clinical stability or in rare instances of prolonged clinical stability without CHF signs. This approach facilitates individualized CHF management and improves the quality of life of both pets and their owners.

Key words: Discontinue; Furosemide; Long-term follow-up; Pulmonary edema.