Echocardiographic Assessment of Cardiac Function by Conventional and Speckle‐Tracking Echocardiography in Dogs with Patent Ductus Arteriosus

Background Patent ductus arteriosus (PDA) is one of the most common congenital heart defects in dogs. Advanced echocardiographic techniques such as speckle-tracking echocardiography (STE) have not been extensively used to evaluate cardiac function in affected dogs. Hypothesis Advanced echocardiographic techniques are more sensitive than standard echocardiographic techniques in analyzing systolic function in dogs with PDA. Animals Forty-four client-owned dogs: 34 dogs with PDA (preoperative evaluation) and 10 healthy sex- and weight-matched controls. Methods Prospective study. Dogs were recruited over a 2-year period. Complete echocardiographic evaluation was performed, including conventional (end-diastolic volumes indexed to body surface area in B and M-mode [EDVIB/M], end-systolic volumes indexed to body surface area in B and M-mode [ESVIB/M], allometric scaling in diastole and systole [AlloD/S], pulmonary flow to systemic flow [Qp/Qs], ejection fraction [EF] and fractional shortening [FS]) and speckle-tracking echocardiography ([STE]: global longitudinal, radial and circumferential strain [S] and strain rate [SR]). Results Dogs with PDA had significantly different EDVIB/M, ESVIB/M, AlloD/S, Qp/Qs and all STE-derived parameters (global longitudinal S and SR, global circumferential S and SR, global radial S and SR)compared to healthy dogs. No correlation was found between standard techniques (EDVIB/M, ESVIB/M, AlloD/S, Qp/Qs) and STE-derived parameters (global longitudinal, circumferential and radial S and SR). Conclusion and Clinical Importance Conventional parameters routinely used to assess systolic function (EF and FS) were not different between the groups; STE-derived parameters identified subtle changes in cardiac systolic function and contractility between the 2 groups of dogs. Based on these findings, STE may be a more appropriate tool to assess cardiac contractility in dogs with PDA.