Late ventricular potentials and QT dispersion in familial dysautonomia

Familial dysautonomia is a worldwide disorder characterized by maldevelopment and dysfunction of the autonomic and sensory systems. Despite major improvements in disease management in recent years, sudden death remains the cause of death in up to 43% of patients. The aim of this study was to evaluate electrocardiographic markers of sudden death in familial dysautonomia. A comparative case series design was used. Electrocardiographic measurements were performed in 13 patients with familial dysautonomia, 7 male and 6 female, aged 9-46 years. QT was measured from all leads and corrected QT (QTc) was calculated with the Bazett formula. QT dispersion (QTd), a marker of arrhythmogenicity, was calculated and corrected for heart rate. Late ventricular potential parameters, predictive of arrhythmias, were calculated as well. Findings were compared to a matched control group using the Mann-Whitney-Wilcoxon test. A prolonged QT interval was noted in 30.7% of patients. Several QT dispersion parameters were significantly abnormal in the study group compared to the controls. All late potential parameters were within normal range in both groups. In conclusion, patients with familial dysautonomia commonly have electrocardiographic abnormalities and may be at a higher risk for adverse cardiac events.