Is There Any Correlation Between QT Dispersion and Echocardiographic Indices in Term Neonates with and Without Maternal Gestational Diabetes Mellitus?

Abstract

Background: Gestational diabetes mellitus (GDM) can cause diastolic dysfunction and asymmetric ventricular septal hypertrophy in infants of gestational diabetic mothers (IGDMs). Ventricular thickness can affect QT interval and other QT parameters. Objectives: This study aimed to evaluate and compare the duration of QT, corrected QT (QTc), QT dispersion (QTD), and echocardiographic indices in two groups of neonates of mothers with and without GDM. Methods: In this case-control study, 76 term neonates were enrolled. The case group (n = 38) included IGDM, and the control group (n = 38) included neonates born to healthy mothers. The QT, QTD, and QTc were calculated based on electrocardiographic results. Ejection fraction (EF), interventricular septal thickness at the end of diastole (IVSTD), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), and left ventricular posterior wall thickness (LVPWT) were evaluated by performing echocardiography, and the two groups were compared regarding them. Data were analyzed using SPSS version 21. Results: In this study, neonates' mean age and weight were 4.18 ± 1.3 days and 3418.16 ± 549.24 grams, respectively. As for the gender of neonates, 68.4% in the case group and 47.4% in the control group were female. The two groups had no significant difference regarding age, weight, and sex (P > 0.05). Minimum QTc (QTc min) was significantly higher in the case group (P = 0.046). Considerably lower EF and higher IVSTD were found in the case group (P = 0.011 and P = 0.05 respectively). In univariate analysis, echocardiographic parameters were not the predictors of QTD (P > 0.05); in multivariate analysis, however, QTD was significantly correlated with LVEDD (P = 0.001) and LVESD (P = 0.015). Conclusions: A higher proportion of septal hypertrophy was detected in IGDMs compared to infants of the healthy mothers without any correlation with ECG indices. This involvement was accompanied by relatively decreased EF verified by echocardiography. Most ECG findings, including QTD values, had no linear relationship with echocardiographic parameters except for LVEDD and LVESD.