Repeatability and reproducibility of right ventricular Tei index valves derived from three echocardiographic methods for evaluation of cardiac function in dogs

OBJECTIVE To evaluate repeatability and reproducibility of right ventricular Tei index (RTX) values derived from dual pulsed-wave Doppler, conventional pulsed-wave Doppler, and tissue Doppler echocardiography and to investigate relationships and repeatability among the 3 methods in healthy dogs. ANIMALS 6 healthy adult Beagles. PROCEDURE Echocardiography was performed on each dog on different days for 2 weeks (3 times/d) by 2 echocardiographers. Intraobserver within- and between-day and interobserver coefficients of variation (CV(s)) and intraclass correlation coefficients (ICCs) for RTX(s) derived from dual pulse-waved Doppler (RTX(DPD)), conventional pulsed-wave Doppler (RTX(PD)), and tissue Doppler (RTX(TD)) methods were determined. Degrees of agreement among RTX values derived from the 3 methods were assessed by modified Bland-Altman analysis. RESULTS Least squares mean (95% confidence interval) RTX(td) was 0.50 (0.46 to 0.54), which was significantly higher than that for RTX(DPD) (0.27 [0.23 to 0.31]) and RTX(PD) (0.25 [0.21 to 0.29]). Agreement between RTX(DPD) and RTX(PD) was good (bias [mean difference], 0.04 [95% confidence interval, −0.03 to 0.10]). The RTX(dpd) had high within-day (CV, 6.1; ICC, 0.77) and interobserver (CV, 3.5; ICC, 0.83) repeatability, but between-day repeatability was not high. The RTXtd had high within-day repeatability (CV, 6.0; ICC, 0.80), but between-day and interobserver repeatability were not high. Within-day, between-day, and interobserver repeatability of RTXPD were not high. CONCLUSIONS AND CLINICAL RELEVANCE RTX(dpd) measurement was a repeatable and reproducible method of cardiac evaluation in healthy dogs. The RTX(TD) values were significantly higher than the RTX(DPD) and RTX(PD) values; therefore, RTX values derived from different echocardiographic methods should be interpreted with caution.