QT dispersion as a predictor of arrhythmic events in patients with ankylosing spondylitis.

OBJECTIVE The aim of the study was to evaluate QT dispersion (QTd), an indicator of repolarization heterogeneity, and its relation to ventricular arrhythmias in patients with ankylosing spondylitis (AS). METHODS A full history, clinical examination, electrocardiograms and 24-h Holter monitoring were performed in 88 AS patients and 31 volunteers of similar age and sex. Groups were compared based on electrocardiographic abnormality, QTd, arrhythmias and heart blocks. RESULTS QTd and corrected QTd (QTcd) were significantly greater in AS patients than controls (QTd, 52.8 +/- 15.1 vs 35.5 +/- 8.9 ms, P: < 0.0001; QTcd, 60.3 +/- 16.1 vs 39.4 +/- 10.7 ms, P: < 0.0001). The magnitudes of these parameters were associated with the duration of the disease (QTd, r = 0.56, P: < 0.01; QTcd, r = 0.60, P: < 0.001). The frequency of ventricular extrasystoles was found to be correlated with QTd (r = 0.35, P: < 0.01) and QTcd (r = 0.33, P: < 0. 01). CONCLUSION Involvement of the heart may be seen in AS during the early clinical course of the disease. QTd may give clues about the presence of arrhythmias and can be used as a new technique for the evaluation of asymptomatic patients. Earlier detection of cardiac involvement could alter the prognosis of the patients.