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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.

The aim of this study was to investigate increase of QTc dispersion and P-wave dispersion during migraine attacks. Fifty-five patients (16-65 years of age, 49 women, six men) with migraine were included in our study. Heart rate, QTc interval, maximum and minimum QTc interval, QTc dispersion, maximum and minimum P-wave duration and P-wave dispersion were measured from 12-lead ECG recording during migraine attacks and pain-free periods. ECGs were transferred to a personal computer via a scanner and then used for magnification of x400 by Adobe Photoshop software. Maximum QTc interval (454 +/- 24 ms vs. 429 +/- 23 ms, P < 0.001), QTc interval (443 +/- 26 ms vs. 408 +/- 22 ms, P < 0.001) and QTc dispersion (63 +/- 18 ms vs. 43 +/- 14 ms, P < 0.001) were found significantly higher during migraine attacks compared with pain-free periods. Maximum P-wave duration (107 +/- 11 ms vs. 100 +/- 11 ms, P < 0.001) and P-wave dispersion (45 +/- 13 ms vs. 35 +/- 13 ms, P< 0.001) were found higher during migraine attacks than pain-free periods. We concluded that migraine attacks are associated with increased QTc and P-wave dispersion compared with pain-free periods.

Subclinical peripheral nerve involvement may be seen in SCD patients. Electrophysiological examinations are recommended in routine examination to diagnose early neuropathy in SCD patients without neurologic symptoms.