Absence of cardiac toxicity of zidovudine in infants

Background: Some evidence suggests that perinatal exposure to zidovudine may cause cardiac abnormalities in infants. We prospectively studied left ventricular structure and function in infants born to mothers infected with the human immunodeficiency virus (HIV) in order to determine whether there was evidence of zidovudine cardiac toxicity after perinatal exposure. Methods: We followed a group of infants born to HIV-infected women from birth to five years of age with echocardiographic studies every four to six months. Serial echocardiograms were obtained for 382 infants without HIV infection (36 with zidovudine exposure) and 58 HIV-infected infants (12 with zidovudine exposure). Repeated-measures analysis was used to examine four measures 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 abnormalities 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 percentage 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 14 months was similar in those never exposed to zidovudine (35.4 percent) and 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 fractional shortening (shortening of 25 percent or less) during the first 14 months of life. No child over the age of 10 months had depressed fractional shortening. Conclusions: Zidovudine was not associated with acute or chronic abnormalities in left ventricular structure or function in infants exposed to the drug in the perinatal period. (N Engl J Med 2000;343:759-66.) (C) 2000, Massachusetts Medical Society.