Normal values of the canine M-mode echocardiogram

Area of Science:

• Veterinary Cardiology
• Echocardiography
• Canine Physiology

Background:

• Echocardiography is crucial for assessing cardiac function in dogs.
• Establishing reference ranges for echocardiographic parameters is essential for accurate diagnosis.
• Understanding the relationship between body weight and cardiac dimensions is important for interpreting echocardiograms.

Purpose of the Study:

• To correlate M-mode echocardiographic measurements with body weight in healthy dogs.
• To identify echocardiographic parameters that exhibit a linear relationship with body weight.
• To determine if fractional shortening and atrial to aortic root ratio are weight-dependent.

Main Methods:

• M-mode echocardiograms were performed on 40 healthy, unsedated dogs in a left lateral recumbent position.
• Fifteen echocardiographic measurements were recorded.
• Linear regression analysis was used to correlate measurements with body weights.

Main Results:

• Left ventricular internal dimensions (systole and diastole), left ventricular wall thickness, aortic root dimension, and left atrial dimension showed high correlation coefficients (r2 ranging from 0.619 to 0.756) with body weight.
• Fractional shortening of the left ventricle (39% +/- 6%) and the left atrial to aortic root ratio (0.99 +/- 0.10) did not demonstrate a linear relationship with body weight and remained relatively constant.

Conclusions:

• Specific echocardiographic measurements in dogs, including ventricular and atrial dimensions, are significantly influenced by body weight.
• Fractional shortening and the left atrial to aortic root ratio appear to be independent of body weight in healthy dogs, suggesting their utility as stable indicators of cardiac function across different sizes.