QT interval dispersion in North Indian children with Kawasaki disease without overt coronary artery abnormalities

Increased QT interval dispersion has been associated with an increased risk for ventricular arrhythmias and sudden cardiac events. We examined the QT interval dispersion in 20 North Indian children with Kawasaki disease (KD) with no coronary artery abnormalities on echocardiography compared the same with matched controls. The study population consisted of 20 children in convalescent phase of KD and 20 age and sex-matched healthy controls. Intervals were measured with the use of a digital caliper with least count of 0.01 mm by a single blinded observer. The QTc dispersion was calculated as the difference between the maximum and minimum corrected QT intervals in 12 and 8 leads (i.e. the 6 precordial leads, the shortest extremity lead, and the median of the 5 other extremity leads). Of the 480 leads obtained (12 per subject), 36 were excluded from analysis (15 because of poor T wave formation and 11 because of presence of U waves). Children with KD had significantly higher QTc dispersion in 12 lead (67.08 ± 17.72 ms compared to 47.63 ± 16.48 ms in controls P ≤ 0.001) as well as 8 lead (60.51 ± 18.54 ms compared to 42.92 ± 18.03 ms in controls P ≤ 0.001) analysis. There was no correlation between delay in IVIG therapy and QT interval dispersion. In conclusion, QT interval dispersion is significantly increased in North Indian children with KD. The dispersion is indicative of inhomogenous ventricular repolarization and may represent increased risk for developing ventricular arrhythmia in this population.