Increased QT dispersion in sickle cell disease: effect of pulmonary hypertension.

BACKGROUND

QT dispersion has been proposed to be a predictor of adverse outcomes in a variety of cardiac disease states. The objective of this study was to examine QT dispersion in patients with sickle cell disease (SCD) and to assess the effect of pulmonary hypertension (PHT) on QT dispersion.

METHODS

We performed Doppler echocardiographic assessments of pulmonary artery systolic pressure in 73 (mean age 18.5 +/- 8.0 years) steady-state SCD patients and 25 (mean age 19.6 +/- 7.2 years) healthy subjects. Resting 12-lead electrocardiogram was recorded and QT dispersion was calculated as the difference between maximum and minimum QT intervals. Bazett's formula was used to obtain a rate-corrected value of the QT interval (QTc).

RESULTS

Maximum QTc, minimum QTc and QTc dispersion were significantly increased in SCD patients compared to the control subjects (p < 0.0001, p < 0.05, p < 0.0001, respectively). Among SCD patients, patients with PHT had higher maximum QTc and QTc dispersion than patients without PHT (p < 0.0001). However, minimum QTc showed no significant differences between the two patient groups.

CONCLUSION

QTc dispersion is significantly increased in SCD patients, especially those with PHT indicating regional inhomogeneity of ventricular repolarization.