Comparative study of 4 echocardiographic methods of left ventricular measurement in German Shepherd dogs.

Objectives: To compare dimensions and shortening fraction (SF) of the left ventricle (LV) obtained from two-dimensional (2D) and M-mode imaging of short and long-axis views.

Animals: 40 healthy, adult German Shepherd dogs.

Methods: Left ventricular measurements were obtained using 4 echocardiographic methods: M-mode in short and long-axis and 2D imaging in short and long-axis. The methods were compared by studying the effects of imaging mode and axis on LV parameters, taking into account the influence of weight and gender.

Results: Mean LV end-diastolic diameter was greater in short-axis views. However, this difference was not considered clinically relevant. Mean SF was higher when derived from 2D measurements with poor agreement among methods. A combined influence of axis, gender, and weight was observed on interventricular septal thickness in end diastole with poor agreement among methods.

Conclusions: Some LV parameters were significantly affected by mode and axis, either in isolation or in combination with weight and gender, although the differences observed were not always clinically relevant. These findings show that using the different echocardiographic methods interchangeably to assess LV dimensions should be done with caution.