Temporal changes in the presence and intensity of innocent cardiac murmurs in clinically healthy Cairn terrier and Dachshund puppies between 4 and 8 weeks of age.

BACKGROUND

Spontaneous week-to-week variation in the presence and intensity of innocent cardiac murmurs in individual puppies is unknown.

METHODS

Sixty privately owned, clinically healthy Cairn terrier and Dachshund puppies between 4 and 8 weeks of age were included. All dogs underwent weekly cardiac auscultation at the breeders' home by a veterinary cardiology specialist using an acoustic stethoscope. On each occasion, a phonocardiogram was recorded with an electronic stethoscope. Furthermore, all dogs were auscultated once at a first opinion veterinary practise and once at the authors' institution, where they also underwent an echocardiographic examination.

RESULTS

Two-hundred and eighty-one auscultations were conducted on 32 Cairn terriers and 28 Dachshunds, at the breeders' homes. Innocent murmurs were detected in 19 puppies. Two of these puppies had a detectable murmur on each auscultation. In five of the puppies, the murmur became undetectable during the observation period and in 12 puppies the murmur was intermittently audible. Auscultation at the authors' institution had an unpredictable effect on murmur presence and intensity. Phonocardiography revealed murmurs in 42 puppies. Interpretation of phonocardiograms by two independent observers showed nearly perfect agreement (κ = 0.859).

CONCLUSIONS

Remarkable and unpredictable spontaneous week-to-week variation was documented in the presence and intensity of innocent murmurs.