Introduction:
Infants of diabetic mothers (IDMs) with cardiac hypertrophy are recognized to have impaired myocardial performance, but less is known about ventricular function in those without hypertrophy. We hypothesized that, in asymptomatic newborns with normal echocardiograms, tissue Doppler imaging (TDI) indices of cardiac function would be decreased in IDMs compared to controls.
Methods:
This retrospective case-control study involved IDMs ≥ 36 weeks gestational age, at 0 to 7 days of life. Subjects with cardiorespiratory symptoms, ventricular hypertrophy or dysfunction, or any echocardiographic abnormality (other than a patent ductus arteriosus before 4 days of life, or a patent foramen ovale) were excluded. Each subject was matched with 3 controls (healthy infants of non-diabetic mothers) by age (0-24, 25-48, 49-72, or > 72 hours of life), birth weight (± 0.5 kg), body surface area (± 0.03 m
2
), and by the ultrasound system utilized. TDI systolic (S’), early diastolic (E’), and late diastolic (A’) velocities were measured at the mitral valve (MV) annulus, basal ventricular septum, and tricuspid valve (TV) annulus, and were averaged from 3 consecutive cardiac cycles. Early Doppler inflow velocity to E’ ratios (E/E’) were calculated.
Results:
Seventy cases (39 male) were identified: first 24 hours (h) of life (n=18), 25-48 h (n=22), 49-72 h (n=14), and > 72 h (n=16). Maternal diabetes was gestational in 60 cases, and pre-existing in 10. Median gestational age was 38 6/7 weeks (range 36-41 2/7), median birth weight 3.65 kg (2.56-5.38), and median BSA 0.22 m
2
(0.17-0.27). Ultrasound system vendors included Siemens
®
(n=46), Philips
®
(n=23), and General Electric
®
(n=1). Cases were matched with 210 controls.
IDMs had significantly lower S’ (
p
≤ 0.05) and E’ (
p
≤ 0.01) velocities, and significantly higher E/E’ ratios (
p
≤ 0.01) at the MV, basal septum, and TV compared to controls (Wilcoxon rank-sum test). There were no significant differences in A’ values between groups. Intraclass correlation demonstrated 84-99% interobserver and 98-99% intraobserver reliability.
Conclusions:
In asymptomatic newborn IDMs without cardiac hypertrophy, TDI suggests a subclinical decrease in systolic and diastolic myocardial function compared to controls.