Pulsed wave tissue Doppler imaging of the left ventricle in foals: Feasibility, inter‐ and intra‐observer variability and wave pattern over the first days of life

Background Tissue Doppler imaging (TDI) may improve the assessment of myocardial function in neonatal foals. Objectives To document the feasibility of left ventricular pulsed wave (PW) TDI, inter‐ and intra‐observer variability and wave pattern over the first 5 days of life. Study Design Prospective observational study. Methods Transthoracic echocardiography was performed in 25 healthy Standardbred foals within the first 24 h after birth (T1), between 60–84 h (T2), and 108–132 h (T3) after birth using right parasternal short‐axis (R‐LV SAX) and subcostal long‐axis views at the mitral annulus, both at the interventricular septum (SC‐MV IVS) and free wall (SC‐MV FW). Systolic (S 1 , S m ) and diastolic (E 1 , E m , A m ) peak velocities were measured at each site. Intra‐ and inter‐observer variability was assessed using intraclass correlation coefficients (ICC). Longitudinal changes were analysed using Friedman's test with Sidak‐adjusted pairwise comparisons. E m and A m were compared using the paired Wilcoxon test. Results Pulsed wave tissue Doppler imaging was feasible in all foals. S 1 and E 1 were frequently indistinguishable. ICCs showed excellent agreement for most variables; measurement variability was low. S m (R‐LV SAX: T1 = 9.3 [8.2–11.0] cm/s; T3 = 12 [11.1–12.7] cm/s; p < 0.01), E m (R‐LV SAX: T1 = 15.8 [14.1–20.1] cm/s; T3 = 22.1 [20.2–25.5] cm/s; p = 0.003; SC‐MV FW: T1 = 16.9 [15.2–20.6] cm/s; T3 = 21.0 [18.1–22.3] cm/s; p = 0.019) and R‐LV SAX E m /A m (T1 = 1.5 [1.3–1.9] cm/s; T3 = 1.9 [1.7–2.6] cm/s; p = 0.003) increased over time. E m was higher than A m in the R‐LV SAX view at all time points. Main Limitation Effective sample size varied across analyses. Conclusions Pulsed wave tissue Doppler imaging was feasible. S m and E m increased over time, while A m remained stable, indicating early ventricular adaptation to extra‐uterine life. PW TDI may be a useful tool in myocardial function monitoring of neonatal foals.