Novel color M-mode echocardiography for non-invasive assessment of the intraventricular pressure in goats: Feasibility, repeatability, and the effect of sedation

BACKGROUND: The intraventricular pressure difference (IVPD) and intraventricular pressure gradients (IVPG), estimated from color M-mode echocardiography (CMME) of the transmitral flow, have been introduced as novel indices for the evaluation of heart functions. Until now, no study demonstrated the feasibility of the CMME approach to measure IVPD and IVPG in any farm animals. The aim of this study was to assess the feasibility and repeatability of CMME-derived IVPD and IVPG variables in goats and explore the effect of sedation on the measured variables. MATERIALS AND METHODS: Sixteen male Shiba goats were included in this study and underwent conventional echocardiography. Eight goats were used in the repeatability of IVPD/IVPG variables. Another eight goats were used to evaluate the effect of sedation by xylazine on IVPD/IVPG measurements. CMME between the base and the apex of the left ventricle was carried out. The IVPD and IVPG were analyzed using in-house code software. The IVPD and IVPG were expressed as total, basal, mid-to-apical, mid, and apical segments. Data analysis including the imaging quality score (IQS), repeatability, variability, intraclass correlation coefficient (ICC), as well as the effect size of sedation on the measured variables was calculated. RESULTS: IVPD and IVPG variables from CMME were feasible in all goats. Low to moderate variability of IVPD and IVPG variables was observed (CV 95% <25%) except for the apical IVPD and apical IVPG. The IVPD/IVPG measurements were repeatable without a significant effect of animal or time on the obtained measurements. The overall ICC was higher than 0.75 in all variables except for the apical segment. Xylazine administration reduced the total, basal, and mid parts of IVPD and IVPG with a large effect size (biserial ranked correlation; rc > 0.8). CONCLUSION: We reported, for the first time, IVPD and IVPG measurements by CMME in goats. The assessment of IVPD and IVPG by CMME is feasible in goats which can be evaluated in further cardiovascular or pharmacological studies in this species.