Evaluation of Fetal Heart Using Fetal Heart Quantification (fetalHQ) Technique in an Indian Cohort.

Objective: To evaluate the intra- and interobserver reproducibility of parameters used to determine cardiac morphometry and deformation using FetalHQ in Indian population.

Methodology: Two operators blinded to each other performed FetalHQ analysis independently on 35 normal fetuses of gestational age between 18 + 0 and 37 + 0 weeks and days. Intra- and interobserver correlation coefficient and limits of agreement were ascertained for parameters obtained from HQ analysis.

Results: Excellent reproducibility (ICC > 0.9) was observed for global morphometric parameters. Ejection fraction, stroke volume, stroke volume/kg demonstrated excellent reliability (ICC > 0.9), cardiac output, fractional area change showed a lower correlation (ICC < 0.8), and right and left ventricular global strain showed no correlation. Twenty-four segment sphericity index of left ventricle (LV) and right ventricle (RV) showed low to moderate correlation (LV-ICC 0.48-0.79; RV-ICC 0.43-0.82). Fractional shortening (FS) showed poor intraobserver reliability in RV.

Conclusion: FetalHQ provides reliable estimates of the global cardiac morphometry but not for global cardiac strain. Regional transverse contractility represented by FS has poor correlation in right ventricle, especially in the apical region, possibly due to moderator band. Nevertheless, it is a promising tool which requires technical advancements and validation to improve its accuracy and reliability.