Two-dimensional and M-mode echocardiographic indices in the normal Taiwanese dogs

Thirty-four adult healthy dogs (16 males and 18 females) weighing 4.6 to 18.9 kg (mean =+-SD, 11.2 =+-3.4 kg) were studied by both two-dimensional and M-mode echocardiography. All tested subjects were mixed-breed companion dogs with the age ranging from 1.3 to 8 years old. During recording, dogs were kept in lateral recumbency without giving any chemical restraint. Two-dimensional echocardiographic images were obtained from left caudal (apical) parasternal location. The M-mode echocardiography was performed from the right parasternal 10ng-axis view. Prior to presenting these values, each set of data was validated by both normality test and descriptive statistics. Parameters were also statistically evaluated to determine whether a correlation to age, gender, heart rate, body weight, and body surface area existed. In conclusion, the presented reference values are useful especially when the tested dogs are fitted in the above categories. Many values, being not correlated to age, sex, and body size, provide good indicators for evaluation of cardiac function. They are ejection fraction, fractional shortening, fractional thickness, interventricular septal thickness/1eft ventricular posterior wall thickness ratio, left atrial dimension/aortic root dimension ratio, systolic time intervals, indices in MV study D-E excursion, E-F slope, E-septal separation, E-septal separation/1eft ventricular diastolic dimension ratio), and stroke volume index.