Tissue velocity imaging in healthy dogs

Objective of the study was to evaluate tissue velocity imaging (TVI) with respect to its reproducibility and to introduce reference values in a large canine population. In addition, the influence of gender, heart rate, age, weight and breed of the dogs was evaluated. Material and methods: A total of 199 healthy dogs were included. The longitudinal TVI was recorded from an apical four-chamber view using colour Doppler technique in unsedated dogs. Each myocardial wall was recorded as a single wall image, aligning the ultrasound beam as parallel as possible to the longitudinal motion of the respective wall. Off-line analysis was performed using the Q-analysis software. Results: Coefficients of variance for intrareader and interreader variability for each parameter were less than 10.0% and 12.4%, respectively. Tissue velocities were heterogeneously distributed within the myocardium, demonstrating an apico-basal gradient. Whereas gender did not influence TVI variables, heart rate, age, breed and weight had a significant influence on the tissue velocity. Conclusion and clinical relevance: TVI is a sophisticated and promising echocardiographic technique. It is relatively easy to perform and can be included in the evaluation of systolic and diastolic myocardial function in routine daily practice. One limitation is that it is influenced by heart rate, age, breed and weight of the dogs. This study provides a basis for further investigation on this topic and supplies reference values for different weight groups in dogs.