Background: The survival rate for extremely low birth weight (ELBW) infants born preterm is on an increasing upward trend, despite the possibility of neuro-cerebral consequences in later life. To date, scarce information is available on the effect of extreme prematurity on cardiovascular system.
Aim: To verify the presence of standard echocardiographic and ECG alterations in ex-ELBW young healthy adults.
Method: A color Doppler echocardiogram and an ECG were performed on 24 ex-ELBW (4 males and 20 females; mean: 23.2 ± 3.3 years), compared with 24 healthy subjects born at term (C). ECG parameters examined: PR, QT, QT(c), and QT dispersion (QT(d)). Gestational age, birth weight, and duration of stay in neonatal intensive care unit were obtained from clinical records.
Results: Transthoracic echocardiography did not reveal differences between ex-ELBW and C, while a significant difference was displayed by ex-ELBW with regard to PR (141.5 ± 13.4 ms vs. 164.2 ± 24.0 ms, p < 0.0003), QT(c) (417.0 ± 23.6 ms vs. 369.9 ± 19.5 ms, p =0.00001), and QT(d) (30.4 ± 14.1 ms vs. 24.6 ± 8.2 ms, p < 0.00001). In two patients (8.3%), QT(c) exceeded the upper limit of normal range. A statistically significant inverse correlation was observed between QT(c) and gestational age (r = -0.67, p < 0.0003).
Conclusions: QT(c) and QT(d) in ex-ELBW were found to be at the upper limit of normal range and correlated with gestational age and birth weight; in two cases, QT(c) exceeded the upper limit. This study, irrespective of the pathophysiological mechanism involved, underlines a potential risk for ex-ELBW of developing ventricular arrhythmias when using drugs capable of prolonging QT interval.
Summary: QT(c) and QT(d) in young adults previously born preterm with an ELBW (401-1000 g) were generally found to be at the upper limit of normal range and correlated with gestational age and birth weight. This finding underlines a potential risk for ex-ELBW of developing ventricular arrhythmias when using drugs capable of prolonging QT interval.