Volumetric quantification identifies some left atrial dilations undetected by left atrium:aorta ratio measurements: A...

Area of Science:

• Veterinary Cardiology
• Echocardiography
• Canine Heart Disease

Background:

• Degenerative mitral valve disease (DMVD) is the most common cardiac condition in dogs, particularly Cavalier King Charles Spaniels (CKCSs).
• Left atrial (LA) dilation, a consequence of DMVD-induced mitral regurgitation, impacts survival time.
• The left-atrial-to-aortic (LA:Ao) ratio is a common echocardiographic measure of LA size.

Purpose of the Study:

• To compare echocardiographic methods for evaluating LA volume (LAvol) in CKCSs.
• To assess LAvol in relation to DMVD severity.
• To compare the efficacy of LAvol versus LA:Ao ratio in identifying LA enlargement in subclinical DMVD (ACVIM stage B).

Main Methods:

• 155 CKCSs (healthy and DMVD-affected) were prospectively enrolled.
• Variability and concordance of different LAvol methods (monoplane/biplane SMOD, ALM) were assessed.
• LA volumes were analyzed according to 2019 ACVIM disease stages.

Main Results:

• Monoplane methods and ALM yielded higher LAvol measurements than biplane methods and SMOD.
• Left atrial volumes significantly increased with DMVD severity (ACVIM stages).
• 37% of stage B1 CKCSs showed LA enlargement via LAvol/body weight (LASvol/BW), with lower values in dogs with regurgitation fraction ≤30%.

Conclusions:

• Echocardiographic LAvol quantification methods are not interchangeable in CKCSs.
• LAvol measurement is superior to linear measurements (LA:Ao ratio) for detecting LA enlargement in stage B CKCSs.
• This highlights the importance of accurate LA volume assessment in early canine heart disease detection.