The Use of 3-D Models of Echocardiographic Imaging Planes for Teaching Echocardiography Techniques for Use in Dogs and Cats.

Echocardiography is an invaluable technique for the diagnosis of heart disease. The aim of this study was to develop 3-D models of healthy and diseased hearts of dogs and cats, and to evaluate their effectiveness in assisting veterinary undergraduates to understand echocardiographic imaging planes. Resin models depicting the main echocardiographic imaging planes of normal hearts were created, as well as example hearts with features of mitral degeneration in dogs and hypertrophic cardiomyopathy in cats. After a theoretical class, fourth-year students were randomly assigned to one of two groups (model group or control group). The model group had access to the 3-D models, along with self-explanatory text about echocardiographic imaging planes; the control group only had access to the self-explanatory text. Both groups were allowed 2 weeks to study their allocated resources, after which the students undertook an assessment to evaluate their learning and completed a questionnaire about their experiences and satisfaction with the respective teaching method. A total of 39 students participated in the study, 19 in the model group and 20 in the control group. Students assigned to the model group spent more time studying (p = 0.0027). The proportion of students who achieved a satisfactory grade in the assessment was 89.5% in the model group and 60% in the control group (p = 0.0449). The 3-D models facilitated, and significantly improved, the identification of cardiac structures and disease-associated abnormalities, and the learning process in general. Additionally, the models seemed to provide greater student motivation for studying echocardiography.

Assessment of heart rate turbulence in dogs with myxomatous mitral valve disease.

BACKGROUND: Myxomatous mitral valve degeneration (MMVD) is the most common heart disease affecting small dogs, it reduces cardiac output resulting in compensatory adaptation of the autonomic nervous system. Chronically, it leads to reduced heart rate variability (HRV) which is an accurate marker for autonomic balance. More than two decades ago in human medicine an indicator of autonomic balance that happens after a premature ventricular beat, it was described as heart rate turbulence (HRT). In humans with ischemic heart disease, the absence of HRT has proven to be a more accurate and an independent indicator of mortality than known HRV parameters. Currently, there are very few studies of HRT in dogs and it is still not tested in small dogs within different stages of myxomatous mitral valve disease. AIM: The aim of this study was to assess the HRT indicators, onset and slope, in small dogs with myxomatous mitral valve disease and to statistically test it. METHODS: Dogs under 25 kg had electrocardiogram and echocardiography performed and, in some patients, holter monitoring was carried out. Data were divided into groups B1, B2, C, and D for mean comparison with analysis of variance and Tukey test. In addition, receiver operating characteristic (ROC) curve for differentiating among symptomatic and asymptomatic dogs and for differentiating between remodeled and non-remodeled hearts. The Pearson was executed after correlations of turbulence onset (TO) and turbulence slope (TS) with commonly used echocardiographic parameters. RESULTS: Variance analyses held significant differences in TO and TS between stages B1 from stages C and D, while B2 held similarity to the other groups. In the receiver operating curve was found a very good area under the curve for differentiating among symptomatic and asymptomatic dogs and remodeled and non-remodeled dogs. Few echocardiography parameters held weak correlation with TO while others held weak to moderate correlation with TS. CONCLUSION: In dogs with MMVD and without other diseases, HRT is a feasible indicator for autonomic balance. Our result suggests HRT changes as the MMVD progresses and congestive heart failure is present. More studies with HRT are needed. The number of ventricular premature contractions (VPCs) may be the strongest limitation for the technique.