Background : Antenatal exposure to the Zika virus (ZIKV) is related to severe neurological, ophthalmological and orthopedic manifestations called congenital Zika syndrome (CZS), but no changes in the electrical activity of the heart have been found. A higher prevalence of structural cardiac changes has been described in CZS patients when compared to the general population of live births. To describe 24-hour Holter findings in infants with confirmed antenatal exposure to ZIKV. Methods : Cross-sectional study of 24-hour Holter findings in infants with antenatal exposure to ZIKV confirmed by positive polymerase chain reaction(PCR) . Patients of the cohort of newborns and infants exposed intrautero to the ZIKV which began in November 2015 and continues to date and were hospitalized for clinical or surgical reasons were included. The 24-hour Holter monitoring was performed the day before discharge. Data analysis was descriptive and included subgroups of patients according to the presence of CZS and severe microcephaly. Heart rate, ST segment, QT interval and arrhythmias were evaluated. To evaluate heart rate variability (HRV) we used time domain analysis. The Mann-Whitney test was performed to verify significant differences between the subgroups of patients. Results : The sample consisted of 15 infants with average age of 16 months and 12 were diagnosed with CZS (8 had severe microcephaly). PCR at birth was positive in 8 newborn and 7 had positive maternal PCR during pregnancy. No arrhythmias or QT interval changes were observed. The Mann-Whitney test showed a significant difference between patients with and without CZS and with and without severe microcephaly, with HRV being lower in the groups with severe microcephaly and CZS. Conclusions : The study suggests that the HRV evaluation can be used as a sentinel event to assess the possibility of progressive neurological impairment in newborns with antenatal exposure to ZIKV, allowing early initiation of stimulation therapies in addition to indicating that cardiovascular complications may arise in the medium and long term.