McGill Journal of Medicine (Jun 1996)
Cardiac Doppler Flow Velocities in Fetuses of Well- Controlled Insulin-Dependent Diabetic Mothers
Abstract
The advent of Doppler echocardiography has permitted noninvasive examination of the fetal heart. In this study, computer-assisted cardiac Doppler flow velocity waveform (DFVW) analysis was used to determine whether diastolic dysfunction is manifest in the fetuses of diabetic mothers. Diastolic atrioventricular (AV) valve flow was measured in the fetuses of 40 women with well-controlled insulin-dependent diabetes mellitus (IDDM) at 18 to 22 weeks (timepoint A) and 30 to 35 weeks (timepoint B) gestation. These subjects were compared to 40 age-matched pregnant non-diabetic controls, and their maternal glycosylated hemoglobin HbA1c fractions (%) were measured to gauge the adequacy of glycemic control. HbA1c fractions showed no statistically significant difference between timepoints A and B (4.85 ± 0.2% and 5.16 ± 0.3%, respectively), and demonstrated a well-controlled diabetic state. At timepoint A, the peak velocity of rapid ventricular filling [E (cm/s)] through both AV valves, the peak velocity of atrial contraction [A (cm/s)] through the tricuspid valve, and the flow integral measurement for atrial contraction [AI (cm)] through the tricuspid valve were significantly (p < 0.05) higher than those measured in the controls. Peak velocities of atrial contraction and rapid ventricular filling (A and E, respectively) for both valves, as well as the flow integral of rapid ventricular filling (EI) for the tricuspid valve, were significantly (p < 0.05) higher in fetuses of diabetic mothers at timepoint B than in controls. Overall, despite the fact that both IDDM and non-diabetic mothers showed significant (p < 0.05) fetal increases in rapid ventricular filling (E) between the two timepoints, the ratios E/A and EI/AI for both valves were not modified in the two study groups at either gestational age. These results therefore substantiate rare previous findings that only peak velocity of rapid ventricular filling (E) is increased, despite expected changes in E/A and EI/AI ratios, with gestational age. Furthermore, the results of the present study suggest that fetal diastolic function is not adversely affected in well-controlled maternal IDDM.
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