QT Dispersion in Childhood Obstructive Sleep Apnea Syndrome

  • Anant Khositseth, Faculty of Medicine Ramathibodi Hospial, Mahidol University, Thailand
  • Palinee Nantarakchaikul, Faculty of Medicine Ramathibodi Hospial, Mahidol University, Thailand
  • Teeradej Kuptanon, Faculty of Medicine Ramathibodi Hospial, Mahidol University, Thailand
  • Aroonwan Preutthipan, Faculty of Medicine Ramathibodi Hospial, Mahidol University, Thailand

    • The difference between maximal and minimal QT interval and corrected QT (QTc) defined as QT dispersion (QTd) and QTc dispersion (QTcd) may reflect inhomogeneity of repolarization and myocardial electrical instability. Many studies in demonstrated that QTd was significantly higher in obstructive sleep apnea syndrome (OSAS). However, there was no study in childhood OSAS.
    Objective: This study was to evaluate QTd and QTcd in childhood OSAS.
    Patients & Methods: Forty-four children with OSAS (34 males), mean +/- SD of 6.18 +/- 3.49 yrs along with 38 age-, sex-matched healthy children (25 males), 6.62 +/- 2.11 yrs underwent 12-lead ECG. The QT and RR intervals were blinded measured by two independent observers.
    Results: Means QTd and QTcd were significantly higher in OSAS than controls, 51.59 +/- 27.18 vs 39.73 +/- 14.42 ms, (p = 0.014), and 71.16 +/- 28.70 vs 57.23 +/- 18.86 ms, (p = 0.010), respectively. Interestingly, QTd and QTcd in OSAS with obesity (57.04 + 29.97 and 73.18 +/- 30.78 ms) were significantly higher than in control (39.74 +/- 14.42 ms and 57.23 +/- 18.86 ms), p = 0.009 and 0.043, respectively. However, QTd and QTcd in OSAS without obesity (42.94 +/- 19.92 and 67.94 +/- 52.62 ms) were not significantly different. Moreover, there was a correlation between QTd and body mass index (BMI) (r = 0.437, p <0.001).
    Conclusions: QTd and QTcd were significantly increased in childhood OSAS. Obesity may be the factor affected the increased QTd and QTcd in childhood OSAS.