Introduction

Turner syndrome (TS) is a genetic condition caused by the absence of a sex chromosome or abnormalities of the X chromosome. It is reported to be associated with electrocardiogram (ECG) abnormalities, of which a prolonged rate-corrected QT interval (QTc) is the most common one. Our objectives were to evaluate the prevalence of QTc prolongation and to evaluate whether QTc prolongation is associated with a certain karyotype in TS patients of all ages.

Methods

Girls and women with TS visiting the outpatient clinics of our expertise centre were included in this study. Data on age, karyotype (monosomy 45,X and other karyotypes), hypertension and cardiac malformations were obtained from the medical records. QT intervals of computerized and printed 12-leaded ECGs were measured manually by two researchers. Two formulas were used to correct for heart rate: Bazett’s and Hodge’s formula. A QTc interval of >450 ms for girls and >460 ms for women was considered prolonged. Prevalence of QTc prolongation was compared to the general population.

Results

In total 101 girls (age 1-16 years) and 252 women (age 17-65 years) were included. The mean QTc interval using Bazett’s formula was longer compared to Hodge’s formula (420 ± 25 ms versus 400 ± 19 ms, p<0.001). In total, 5% of the population had a prolonged QTc interval using Bazett’s formula (4% in girls and 6% in women) and 0% using Hodge’s formula. Patients with a monosomy 45,X karyotype had a higher basic heart rate compared to the patients with other karyotypes. Yet, there was no clinically relevant difference in QTc interval nor prevalence of QTc prolongation between these two groups, when using both formulas.

Conclusion

This study shows that the QTc interval in girls and women with TS is not prolonged compared to the general population using both Bazett’s and Hodge’s formulas. Patients with monosomy 45,X show no clinically relevant difference in QTc interval nor prevalence of QTc prolongation compared to other karyotypes.