From this thread:
"After reviewing the echo study I am not convinced your patient is in CHF. The presence or absence of CHF cannot be determined by echo. Physical exam, thoracic radiography and the SRR with a proven Lasix response if the SRR is elevated are much more accurate. The echo can readily assess the presence or absence and degree of cardiac pathology and verify the reason for murmur generation and provide info that is consistent or inconsistent with CHF but cannot tell you that CHF is definitely present.
The echo confirms the murmur in this patient is due to MR most likely associated with MMVD in the CKCS. However, the LA and LV size is not consistent with CHF.
I would have the owner log the SRR for 3-4 days and if <30/min stop the pimobendan and enalapril and begin to taper the Lasix dose lower and lower monitoring the SRR at each step.
Client education is important here as it is likely that this dog will go into CHF at some point in the future due to a worsening of the MMVD. Careful monitoring of the SRR will allow you to restart meds when the SRR begins to approach 30/min. No study to date has shown that early intervention with the drugs you are using is beneficial in either prolonging life or prolonging time to onset of CHF."