Which Doppler parameter helps assess fetal myocardial function in echocardiography?

• A. Myocardial performance index (Tei index), calculated from isovolumic contraction time, isovolumic relaxation time, and ejection time.
• B. E/A ratio at the mitral valve.
• C. Ductus venosus Doppler.
• D. A-wave velocity.

Answer: (A)

Global myocardial function in fetal echocardiography is best assessed with the myocardial performance index, also known as the Tei index. This Doppler-derived measure combines systolic and diastolic time intervals to reflect overall heart performance: it sums the isovolumic contraction time and the isovolumic relaxation time and divides by the ejection time. A higher Tei index means poorer myocardial performance, capturing both how the heart contracts and how it relaxes, which is particularly useful when preload and loading conditions can vary in the fetus.

Other Doppler parameters provide important information about specific aspects of filling or circulation but do not offer a single, global assessment of myocardial function. The E/A ratio at the mitral valve looks at the relative contributions of early (E) and late (A) filling and is highly influenced by loading and heart rate in utero, making it less reliable as a sole measure of overall myocardial performance. Ductus venosus Doppler reflects central venous return and filling pressures rather than direct myocardial contractility. A-wave velocity measures atrial contraction contribution to filling and is affected by ventricular compliance and rhythm, not a direct index of overall myocardial function.