Rhodesian Ridgebacks, Borzois, Afghan Hounds, Salukis, and Basenjis have breed-specific reference ranges for vertebral heart size and vertebral left atrial size

Objective: To develop vertebral heart size (VHS) and vertebral left atrial size (VLAS) reference intervals in sighthounds. Methods: Electronic medical records of IDEXX Telemedicine Consultants were searched for Rhodesian Ridgebacks, Borzois, Afghan Hounds, Salukis, and Basenjis undergoing thoracic radiography from January 1, 2021, through April 30, 2023. All measurements of VHS and VLAS were performed by the same board-certified cardiologist. Results: 920 sighthounds (225 Rhodesian Ridgebacks, 196 Borzois, 190 Afghan Hounds, 159 Salukis, and 150 Basenjis) were identified, and 240 (56 Rhodesian Ridgebacks, 47 Borzois, 44 Afghan Hounds, 44 Salukis, and 49 Basenjis) met the inclusion criteria. The remaining 680 dogs were excluded because of malpositioning or incomplete radiographic studies (n = 456), extracardiac disease (139), or cardiac disease (85). The overall reference intervals for all 240 sighthounds were 9.0 to 11.2 vertebrae (v) for VHS and 1.7 to 2.6v for VLAS. Reference intervals were further determined by breed: Rhodesian Ridgeback, 9.3 to 11.5v for VHS and 1.8 to 2.4v for VLAS; Borzois, 8.8 to 10.9v for VHS and 1.7 to 2.3v for VLAS; Afghan Hound, 9.0 to 11.5v for VHS and 1.8 to 2.5v for VLAS; Salukis, 9.4 to 11.8v for VHS and 1.6 to 2.6v for VLAS; and Basenjis, 9.0 to 11.6v for VHS and 1.7 to 2.5v for VLAS. Conclusions: Sighthounds have breed-specific VHS and VLAS reference intervals. Clinical Relevance: The reference ranges presented here could be a diagnostic aid to screen for cardiomegaly in these breeds.