Absence of cardiac toxicity of zidovudine in infants

Background: Some evidence suggests that perinatal exposure to zidovudine ma y cause cardiac abnormalities in infants. We prospectively studied left ven tricular structure and function in infants born to mothers infected with th e human immunodeficiency virus (HIV) in order to determine whether there wa s evidence of zidovudine cardiac toxicity after perinatal exposure. Methods: We followed a group of infants born to HIV-infected women from bir th to five years of age with echocardiographic studies every four to six mo nths. Serial echocardiograms were obtained for 382 infants without HIV infe ction (36 with zidovudine exposure) and 58 HIV-infected infants (12 with zi dovudine exposure). Repeated-measures analysis was used to examine four mea sures of left ventricular structure and function during the first 14 months of life in relation to zidovudine exposure. Results: Zidovudine exposure was not associated with significant abnormalit ies in mean left ventricular fractional shortening, end-diastolic dimension , contractility, or mass in either non-HIV-infected or HIV-infected infants . Among infants without HIV infection, the mean fractional shortening at 10 to 14 months was 38.1 percent for those never exposed to zidovudine and 39 .0 percent for those exposed to zidovudine (mean difference, -0.9 percentag e point; 95 percent confidence interval, -3.1 to 1.3 percentage points; P=0 .43). Among HIV-infected infants, the mean fractional shortening at 10 to 1 4 months was similar in those never exposed to zidovudine (35.4 percent) an d those exposed to the drug (35.3 percent) (mean difference, 0.1 percentage point; 95 percent confidence interval, -3.7 to 3.9 percentage points; P=0. 95). Zidovudine exposure was not significantly related to depressed fractio nal shortening (shortening of 25 percent or less) during the first 14 month s of life. No child over the age of 10 months had depressed fractional shor tening. Conclusions: Zidovudine was not associated with acute or chronic abnormalit ies in left ventricular structure or function in infants exposed to the dru g in the perinatal period. (N Engl J Med 2000;343:759-66.) (C) 2000, Massac husetts Medical Society.