Assessment of right ventricular function in healthy Great Danes and in Great Danes with dilated cardiomyopathy

Right ventricular (RV) dysfunction is a significant negative prognostic indicator in human dilated cardiomyopathy (DCM). Many RV indices are weight-dependent, and there is a lack of reference values for the right heart in giant breed dogs (over 50 kg), including Great Danes (GDs). This study aimed to compare indices of RV function in echocardiographically normal GDs, those with preclinical DCM (PC-DCM), and those with DCM and congestive heart failure (DCM-CHF).

A total of 116 client-owned adult GDs: 74 normal, 31 with PC-DCM, and 11 with DCM-CHF.

A retrospective, single-center cohort study assessed RV function using free-wall RV longitudinal strain (RVLS), strain rate, fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), and pulsed-wave tissue Doppler imaging-derived systolic myocardial velocity of the lateral tricuspid annulus (TDI S'). Relationships between DCM status and RV function indices were analyzed.

RV function, measured by TAPSE (P=0.001), FAC (P<0.001), and TDI S' (P<0.001), decreased in dogs with PC-DCM and DCM-CHF compared to healthy dogs, with FAC being lower in DCM-CHF compared to PC-DCM (P=0.048). RVLS impairment was more significant in the DCM-CHF group than in the PC-DCM group (P=0.048). RVLS had the highest area under the curve (0.899) for differentiating between normal and DCM-CHF dogs.

As DCM progresses, echocardiographic variables of RV function, including TAPSE, FAC, TDI S', RVLS, and strain rate, worsen, indicating impaired RV systolic function in GDs affected by DCM.