Parts of the study were presented at the 16th European Association of Veterinary Diagnostic Imaging Annual Conference, Svolvær, Norway, August 2008.
Size and Shape of Right Heart Chambers in Mitral Valve Regurgitation in Small-Breed Dogs
Article first published online: 5 AUG 2009
Copyright © 2009 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 23, Issue 5, pages 1007–1013, September/October 2009
How to Cite
Carlsson, C., Häggström, J., Eriksson, A., Järvinen, A.-K., Kvart, C. and Lord, P. (2009), Size and Shape of Right Heart Chambers in Mitral Valve Regurgitation in Small-Breed Dogs. Journal of Veterinary Internal Medicine, 23: 1007–1013. doi: 10.1111/j.1939-1676.2009.0359.x
- Issue published online: 1 SEP 2009
- Article first published online: 5 AUG 2009
- Submitted February 4, 2009; Revised April 28, 2009; Accepted June 18, 2009.
- Heart enlargement;
- Heart failure;
- Radionuclide angiocardiogram
Background: The contribution of right heart (RH) chamber enlargement to general heart enlargement seen on thoracic radiographs in mitral regurgitation (MR) is not known.
Objectives: To determine the size and shape of the RH chambers in normal dogs and dogs with varying degrees of MR.
Animals: Fifty-four privately owned dogs: 13 normal, 41 with varying degrees of MR including 25 with congestive heart failure (CHF).
Methods: Archived first pass radionuclide angiocardiograms were used to produce static images of the RH and left heart (LH) chambers. Indexes of size and shape of the RH and LH chambers were related to severity of MR determined by heart rate-normalized pulmonary transit time (nPTT), vertebral heart scale (VHS), and clinical status. RH shape was measured by a circularity index of RH short axis/long axis.
Results: A 2nd degree polynomial fit best described the ratios; RH/LH dimension to nPTT (R2= 0.62) and to VHS (R2= 0.43), RH/LH area to nPTT (R2= 0.64) and to VHS (R2= 0.58), all P < .001. RH circularity was decreased in CHF, P < .001. In CHF, the RH chambers of 16 dogs were both flattened and enlarged, whereas 9 had convex septal borders.
Conclusions: RH chambers are not significantly dilated in dogs with mild to moderate MR without CHF. In CHF, RH chambers enlarge and also may be compressed by the LH chambers. Pulmonary hypertension probably is present in some dogs with CHF. Increased sternal contact is not a useful sign of right-sided heart dilatation in MR.