Evaluation of the left ventricular eccentricity index for assessing dogs classified by pulmonary hypertension probability

Objective To evaluate the left ventricular eccentricity index (EI) across different pulmonary hypertension (PH) probability groups and cardiac cycle phases. Methods This retrospective study enrolled 121 client-owned dogs with PH between February 2020 and July 2024. History, radiography, echocardiography, and other medical recordings were reviewed. Dogs with PH were diagnosed and classified according to the American College of Veterinary Internal Medicine consensus guidelines. The EI was measured at end diastole (EId) and end systole (EIs). The t, Mann-Whitney U, and Kruskal-Wallis tests were used to compare EI between PH groups. Receiver operating characteristic curve analysis was applied to assess the EI for predicting PH and right-sided congestive heart failure. Pearson correlation analysis was used to evaluate the correlation of EId and EIs with both tricuspid regurgitation velocity and right pulmonary artery distensibility index. Results This study enrolled 37 healthy (control) and 84 dogs with PH. Both EId and EIs were significantly different between the control and PH groups (EId/EIs, 1.16/1.13 vs 1.31/1.66). An EIs value of 1.22 distinguished the 2 groups with a sensitivity of 0.7 and specificity of 1 (AUC, 0.78). Both EId and EIs were positively correlated with tricuspid regurgitation velocity but not with the right pulmonary artery distensibility index. Conclusions The EI is useful for evaluating septal flattening in dogs with PH under various conditions. The EId showed inferior power to the EIs in assessing PH but aided screening for right-sided congestive heart failure and volume overload. Clinical Relevance The EI can help clinicians to more accurately assess PH probabilities, specifically regarding ventricles.