(E29) Tissue Doppler Imaging Assessment of the Left Ventricle in Healthy Standardbred Newborn Foals

Abstract:

Background: While tissue Doppler imaging (TDI) is used for left ventricular (LV) assessment in horses, its application has not been described in foals.Hypothesis/

Objectives: To investigate the feasibility of pulsed-wave (PW) TDI for characterization of LV radial and longitudinal wall motion in healthy foals, and to describe TDI features during foals' first days of life.Animals: Seven healthy Standardbred newborn foals.

Methods: Prospective observational study. Foals underwent complete transthoracic echocardiography without sedation at 24 hours, 72 hours and five days of life. In each foal, PW TDI tracings were acquired by multiple views at the level of the interventricular septum and LV free wall to assess radial and longitudinal velocity profiles. Effect of age, body weight, heart rate and echocardiographic views on PW TDI peak velocities, and correlations between parameters were evaluated (linear mixed models, Spearman's rho coefficient).

Results: In all foals, PW TDI velocity profiles were acquirable and interpretable. A 5-wave pattern, characterized by the presence of S1 (peak velocity during isovolumic contraction), Sm (peak systolic velocity), E1 (peak velocity during isovolumic relaxation), Em (peak proto-diastolic velocity) and Am (peak late diastolic velocity) was documented. Interestingly, Sm and Em increased with age, Em and Am were positively correlated with heart rate, while S_m, E_m and A_m were inconsistently correlated with different echocardiographic views.Conclusions and clinical importance: In healthy newborn foals, PW TDI assessment of LV function is feasible, although several variables should be considered for a correct interpretation of velocity profiles, including age.