Shortened QT interval: a distinctive feature of the dysautonomia of chronic fatigue syndrome

Purpose: Because autonomic nervous functioning is frequently abnormal in chronic fatigue syndrome (CFS), we examined whether the corrected QT interval (QTc) in CFS differs from QTc in other populations. Methods: The QTc was calculated at the end of 10 minutes of recumbence and the end of 10 minutes of head-up tilt. In a pilot study, groups of 15 subjects, CFS, and controls, matched for age and sex, were investigated. In a second phase of the study, the QTc was measured in larger groups of CFS (n = 30) and control patients (n = 96) not matched for demographic features. Results: In the pilot study, the average supine QTc in CFS was 0.371 +/- 0.02 seconds and QTc on tilt, 0.385 +/- 0.02 seconds, significantly shorter than in controls (P =.0002 and .0003, respectively). Results of phase II confirmed this data. Conclusions: Relative short QTc intervals are features of the CFS-related dysautonomia. The significance of this finding is discussed. (c) 2006 Elsevier Inc. All rights reserved.