To assess left atrial (LA) function in preterm infants with patent ductus arteriosus (PDA) using vector velocity imaging (VVI).

One hundred and twenty-two preterm infants (<37 gestational weeks of age) were recruited in this study, and echocardiography was performed at both 3 days and 1 month after birth. The preterm infants were divided into three groups according to PDA size and closure during follow-up: control group (40 cases), closing PDA (cPDA) group (38 cases), and open PDA (oPDA) group (44 cases). LA longitudinal global strain (S) and strain rate (SR) were recorded at different cardiac cycle. LA strain (LASs) and LA strain rate (LASRs) were measured at ventricular systole, which represented LA reservoir function, LASe and LASRe were measured at early diastole, which represented the LA conduit function, and LASa and LASRa were measured at late diastole, which represented the LA contraction function. The LA function parameters were compared among the three groups.

At day 3, in the cPDA and oPDA groups, the LASs (26.0%±2.8%, 25.3%±3.5%), LASa (-17.3%±2.0%, -16.8%±2.6%), and LASRa [(-2.47±0.40) s^-1, (-2.41±0.39) s^-1] were all much lower than those in the control group [28.2%±5.1%, (-19.4%±3.4%) s^-1, and (-2.73±0.42) s^-1] (P<0.05 for all). At 1 month, the values in the cPDA group returned to normal, but in the oPDA group, LASs, LASRs, LASa, and LASRa were still significantly lower than those in the control group (P<0.05 for all).

VVI is a useful tool for evaluating LA function. PDA in preterm infants results in left heart volume overload and decreased LA reservoir and contraction function. The LA function might be improved after PDA closure.