Longitudinal Myocardial Deformation Analysis of the Left Ventricle in Dogs with Leishmaniosis Investigated by Speckle-Tracking Echocardiography

Inflammatory myocardial involvement has been reported in canine leishmaniosis (CanL); however, studies evaluating the degree of myocardial dysfunction in affected dogs are limited. This prospective study aimed to investigate myocardial involvement in dogs with CanL using conventional and speckle-tracking echocardiography (STE), focusing on the assessment of left ventricular systolic function and myocardial strain. Symptomatic, initially untreated dogs with a diagnosis of leishmaniosis and free from other vectorborne diseases or underlying heart diseases were enrolled (Leish group). Healthy dogs matched for age, body weight, breed, and sex were selected for the control group (C group). At the time of inclusion (T0) and at each follow-up, laboratory tests as well as conventional echocardiographic examination and STE were performed. For strain analysis, apical longitudinal long-axis 4-chamber, 3-chamber, and 2-chamber views were used (2C, 3C, 4C, respectively) to obtain the average global longitudinal strain (GLSAV), which is recognised to have the maximum reliability as an indicator of left ventricular dysfunction in humans. The software obtains GLSAV by averaging the longitudinal strain values from all left-ventricular segments derived from the multiple apical views. After enrolment, dogs were treated with a combination of meglumine and allopurinol and were monitored for six months. Clinical-pathological and echocardiographic data were collected at followup at 1, 3, and 6 months after the start of treatment (T1, T2, T3) and compared between the two study groups using appropriate statistical tests. Sixteen dogs composed the C group and nine dogs the Leish group. At T0, none of these dogs had abnormalities in cardiac auscultation, plasma cardiac troponin concentration was within the reference range, and standard echocardiographic examination excluded underlying cardiac diseases. The comparison between C and Leish groups did not show a statistically significant difference in any of the strain parameters analysed (GLSAV, GLS4C, GLS3C, GLS2C). Moreover, strain values in the Leish group did not change significantly over time. In conclusion, in this preliminary study on a limited population of dogs with leishmaniosis, both conventional echocardiography and STE failed to reveal clear changes suggestive of left ventricular systolic dysfunction secondary to possible myocarditis or as a consequence of the systemic disease in dogs with active leishmaniosis. However, further STE studies in larger cohorts of dogs with leishmaniosis are needed to confirm and expand our findings.