QT dispersion in patients with arrhythmogenic right ventricular dysplasia

Aims Arrhythmogenic right ventricular dysplasia is a rarely diagnosed cardi omyopathy, but a frequent cause of ventricular arrhythmia and sudden cardia c death. QT interval dispersion, measured as an interlead variability of QT , is a marker of dispersion of ventricular repolarization and, hence, of el ectrical instability. The present study was conducted to assess the occurre nce of QT dispersion and its modulation during treatment with sotalol. Methods Twenty-five patients with the diagnosis of arrhythmogenic right ven tricular dysplasia were studied retrospectively. Fourteen patients were con sidered low risk for malignant ventricular arrhythmia and sudden cardiac de ath, and 11 high risk due to documented sustained ventricular arrhythmia, c ardiac arrest, or sudden cardiac death. Twenty five healthy volunteers serv ed as control subjects. Results Dispersion of repolarization was significantly higher in patients t han in control subjects (QTd and JTd: P<0.05). Dispersion of repolarization was equal in patients both with and without malignant arrhythmias. There w as no significant change in dispersion after treatment with sotalol. Adjace nt QT dispersion between leads V-3-V-4, V-4-V-5 and V-5-V-6, respectively, was higher in patients than in control subjects (P<0.05), while no differen ces were seen in leads V-1-V-2 and V-2-V-3. Conclusion QT interval dispersion is increased in patients with arrhythmoge nic right ventricular dysplasia. However, the degree of dispersion is not r elated to the severity of symptoms, nor is it influenced by treatment with sotalol.