Respiratory rate (RR) monitoring can be a more sensitive, albeit nonspecific, indicator of developing or recurring congestive heart failure (CHF) than radiographs, coughing, overt signs, or biochemical biomarkers. Frequent monitoring of RR may allow for timely therapeutic intervention or modulation in animals with known history of CHF or severe subclinical heart disease. Veterinary cardiologists often recommend monitoring RR in subclinical cardiac patients to help determine onset of CHF or monitor therapy effectiveness in CHF patients.

Anecdotally, a sleeping RR (SRR) <30 breaths/minute excludes CHF as a cause of signs. To confirm this value, a study characterized SRR in apparently healthy adult dogs. Participants collected 12–14 1-minute SRRs in 114 privately-owned adult dogs over 1 week to 2 months. Mean within-dog average (SRRMEAN) was 13 breaths/min. No dogs had a SRRMEAN >23 breaths/min, although 3 had individual single episodes of SRRMEAN >30 breaths/ min. There was no effect on SRRMEAN caused by body weight, age, or geographic location. Results indicated that apparently healthy adult dogs have SRRMEAN <30 breaths/min and rarely exceed this rate at any time.

Source
Sleeping respiratory rates in apparently healthy adult dogs. Rishniw M, Ljungvall i, Porciello F, et al. RES VET SCI 93:965-969, 2012.

For more, see Canine Heart Murmur by Dr. Mark Rishniw