Breed-specific vertebral heart size and vertebral left atrial size reference intervals in Yorkshire Terriers, Pomeranians, Pugs, and Boston Terriers.

Objective: The investigators sought to reanalyze previously published vertebral heart size (VHS) reference intervals in Yorkshire Terriers (YTs), Pomeranians (POMs), Pugs, and Boston Terriers (BTs).

Methods: The electronic medical records of IDEXX Telemedicine Consultants were searched for YTs, POMs, Pugs, and BTs undergoing radiography between January 1, 2023, and March 31, 2023. Dogs were included if they had 2- or 3-view thoracic radiographs performed and no evidence of cardiopulmonary or systemic disease. This was an observational study with the same board-certified cardiologist performing the VHS and vertebral left atrial size (VLAS) measurements in all breeds.

Results: During the study period, a total of 1,776 YTs, 1,431 POMs, 945 Pugs, and 711 BTs were identified. Of these, 1,293 YTs, 1,051 POMs, 554 Pugs, and 515 BTs were excluded leaving 483 YTs, 380 POMs, 391 Pugs, and 196 BTs available for analysis. The reference interval for YTs was 9.0 to 11.4 vertebrae for VHS and 1.7 to 2.4 vertebrae for VLAS. The reference interval for POMs was 9.5 to 12.0 vertebrae for VHS and 1.7 to 2.6 vertebrae for VLAS. The reference interval for Pugs was 9.7 to 12.0 vertebrae for VHS and 1.7 to 2.7 vertebrae for VLAS. The reference interval for BTs was 9.7 to 13.0 vertebrae for VHS and 1.6 to 2.7 vertebrae for VLAS.

Conclusions: Pugs, YTs, POMs, and BTs have breed-specific VHS and VLAS reference intervals.

Clinical Relevance: Clinicians should be aware of these results to accurately diagnose cardiac disease in these breeds.