Atrial and Ventricular Electrocardiographic Dromotropic Disturbances in Down Syndrome Patients with Structurally Normal Heart: A Cross-Sectional Study

We designed a cross-sectional study to determine electrocardiographic disorders in Down syndrome patients with congenitally normal hearts in a bid to predict fatal cardiac arrhythmia in the future.
We investigated 60 children with DS without congenital abnormal hearts. Sixty healthy juveniles were also included in the study as a control group. Physical examination, electrocardiography, and echocardiography were performed in all subjects. Corrected QT interval (QTc) was measured according to Bazett’s formula.
Patients with DS consisted of 32 males (53.33%), and 28 females (46.66%), aged 6–13 (9.21 ± 6.24) years old. Healthy subjects comprised 31 males (51.66%), and 29 females (48.33%) with a mean age of 9.15 ± 5.01. The two groups were significantly different in terms of heart rate (P=0.006), maximum P-wave duration (P=0.001), and P-wave dispersion (PWd, P=0.0001). There was no statistically significant difference regarding minimum P-wave duration (P=0.176). The patients with DS had a greater maximum QTc interval, QT dispersion, and corrected QT interval dispersion (QTc-d) than the healthy control subjects (P=0.001). However, there was no difference in maximum QT interval and minimum QTc interval between the two groups (P=0.67 and P=0.553, respectively). A positive correlation was found between age, heart rate, and all electrocardiographic variables.
All DS patients, even in the absence of concomitant congenital heart disease should be followed up carefully by electrocardiography, looking for increased PWd and QTc-d to detect predisposed cases to arrhythmia.