Abstract
Background:
Transthoracic echocardiography represents the main noninvasive technique for evaluating cardiac morphology and function in dogs. In dogs with particular somatotypes, such as brachymorphic dogs, breed-specific echocardiographic values are needed for a proper echocardiographic interpretation. Nowadays, the Pug represents one of the most popular brachymorphic canine breeds worldwide. However, data on echocardiographic measurements in this breed are currently limited.
Aim:
We aimed to determine echocardiographic values in a population of apparently healthy Pugs, and to assess the possible effects of body weight, age, and sex on selected echocardiographic variables, with particular emphasis on those related to the left-sided cardiac chambers.
Methods:
Apparently healthy Pugs underwent a full physical examination, a one-minute six-lead electrocardiogram, and a complete transthoracic echocardiography. Twenty-four echocardiographic variables were measured combining M-mode, two-dimensional and Doppler modalities, and relative values were determined by applying the statistical procedures recommended by the Clinical and Laboratory Standards Institute. Moreover, the effect of selected demographic variables on echocardiographic measurements were tested using a linear mixed model.
Results:
The investigation included 86 Pugs. Echocardiographic values were provided for each variable and compared with previous veterinary literature. A statistically significant effect of body weight (e.g., end-systolic left ventricular diameter and absolute left atrial diameter), age, and sex was documented for several of the tested variables. Doppler examination demonstrated a trivial pulmonary regurgitation in 24/86 (27.9%) Pugs. Moreover, a persistent left cranial vena cava was suspected in 4/86 (4.7%) dogs.
Conclusion:
Echocardiographic features of the Pug were addressed and echocardiographic values made available for clinical use. Because our findings were obtained using a standardized echocardiographic analysis in a population of 86 healthy Pugs, they may act as a reliable guide for an accurate echocardiographic interpretation in this breed.

Key words: Brachymorphic, Persistent left cranial vena cava, Pulmonary regurgitation, Reference interval, Transthoracic echocardiography