RESUMEN
Objective: To assess QT interval abnormalities among children with breath-holding spells. Methods: This case control study included 204 children (104 cases of breath-holding spells and 100 healthy children) younger than 3 years. Breath-holding spells were evaluated for age of onset, type (pallid/cyanotic), triggering factors, frequency and presence of family history. Twelve- lead surface electrocardiogram (ECG) was analyzed for QT interval (QT), corrected QT interval (QTc), QT dispersion (QTD) and QTc dispersion (QTcD) in milliseconds. Results: The mean (SD) QT, QTc, QTD and QTcD interval in milliseconds were 320 (0.05), 420 (0.07), 61.15 (16.20), 102.3 (17.24), respectively for breath-holding spells as compared to control group [300 (0.02), 370 (0.03), 38.6(14.28), 78.6 (14.28), respectively] (P<0.001). Similarly, pallid breathholding spells had prolonged mean (SD) QT, QTc, QTD and QTcD interval in milliseconds [380 (0.04), 520 (0.08), 78.88 (10.78), 123.33 (10.28), respectively] as compared to cyanotic spells [310 (0.04), 400 (0.04), 57.44 (14.64), 97.90 (15.03), respectively] (P<0.001). The mean QTc interval was 590 (0.03) and 400 (0.04) milliseconds in prolonged and non-prolonged QTc group, respectively (P<0.001). Conclusion: Abnormal QT, QTc, QTD and QTcD were observed among children with breath-holding spells. ECG should be strongly considered, especially in pallid, frequent spells occurring at younger age and having positive family history, to identify long QT syndrome.