Corrected Qt Dispersion in Children with Isolated Uncomplicated Mitral Valve Prolapse

Mitral valve prolapse (MVP) is a relatively frequent valvular abnormality. In both children and adults with MVP, an increased incidence of ventricular arrhythmias has been reported. QT dispersion, defined as the difference in duration between the longest QT interval and the shortest one, for a given set of electrocardiographic leads has been proposed as a sign of regional difference in cardiac repolarization and as a marker of increased risk of ventricular arrhythmias. This study was designed to compare the corrected QT dispersion (QT c D) in children with isolated uncomplicated prolapse with a normal age-and sex-matched group of children. Twenty children with MVP (mean+SD age: 8+5 years) and thirty normal children enrolled in the study. Corrected QT dispersion was manually calculated on their surface electrocardiogram in all of them. QT c D was 39+14.7 and 40+15.2 milliseconds respectively. An unpaired Student t-test was performed. There was no significant difference between the mean value of the two groups (p value<0.01). The findings of our study, besides the reports of increased QT dispersion in adults, suggest that increased QT dispersion in patients with MVP is a time-evolved phenomenon and does not exist from the very early years of age. MJIRI, Vol. 18, No. 2, 107-110, 2004.